JST Study Material

July 8, 2025

JST Study Material

Biology

Biology 10th Class Mcq’s

Chapter 1: Gaseous Exchange

What is the primary site of gaseous exchange in humans? A) Trachea B) Bronchi C) Alveoli ✅ D) Diaphragm Explanation: Alveoli are tiny air sacs with thin walls and a rich capillary network, enabling efficient diffusion of oxygen into the blood and carbon dioxide out.

Which gas is mainly absorbed by blood in the lungs? A) Carbon monoxide B) Oxygen ✅ C) Nitrogen D) Carbon dioxide Explanation: Oxygen from inhaled air diffuses into capillaries in the alveoli and is transported to tissues for cellular respiration.

In plants, gaseous exchange occurs through: A) Cuticle B) Lenticels C) Stomata ✅ D) Phloem Explanation: Stomata are microscopic pores on leaves that regulate the exchange of gases such as O₂ and CO₂.

Which part of the brain controls breathing? A) Cerebrum B) Cerebellum C) Medulla oblongata ✅ D) Thalamus Explanation: The medulla oblongata monitors CO₂ levels and controls involuntary respiratory movements.
Gaseous exchange in unicellular organisms occurs through: A) Gills B) Skin C) Body surface ✅ D) Lungs Explanation: Due to their small size, unicellular organisms like Amoeba use simple diffusion through their membrane for gas exchange.

Which structure prevents food from entering the trachea? A) Epiglottis ✅ B) Glottis C) Larynx D) Pharynx Explanation: The epiglottis covers the trachea during swallowing to prevent food from entering the airway.

The trachea divides into: A) Two lungs B) Two alveoli C) Two bronchi ✅ D) Two pleura Explanation: The trachea splits into two bronchi that carry air into each lung.

In fish, gaseous exchange takes place through: A) Lungs B) Skin C) Gills ✅ D) Spiracles Explanation: Fish use gills for respiration, allowing exchange of gases between water and blood.

Which gas is released during respiration? A) Oxygen B) Hydrogen C) Nitrogen D) Carbon dioxide ✅ Explanation: Carbon dioxide is a waste product of aerobic respiration expelled through exhalation.

The diaphragm is a: A) Bone B) Cartilage C) Muscle ✅ D) Nerve Explanation: The diaphragm is a dome-shaped muscle crucial for inhalation as it contracts and expands the lungs.

Human lungs are enclosed in: A) Thoracic cavity ✅ B) Abdominal cavity C) Buccal cavity D) Pelvic cavity Explanation: The thoracic cavity houses the lungs, protected by the rib cage.

The voice box is also called: A) Trachea B) Larynx ✅ C) Pharynx D) Bronchi Explanation: The larynx contains vocal cords and produces sound as air passes through.

The air sacs in the lungs are: A) Bronchioles B) Alveoli ✅ C) Bronchi D) Capillaries Explanation: Alveoli are the terminal ends of bronchioles where gas exchange occurs.

The breathing rate increases due to: A) Low carbon dioxide B) High oxygen C) High carbon dioxide ✅ D) Low nitrogen Explanation: Increased CO₂ in blood triggers the medulla to accelerate breathing to expel it.

Which is not part of the respiratory system? A) Nasal cavity B) Trachea C) Kidney ✅ D) Lungs Explanation: The kidney belongs to the excretory system, not the respiratory.

Inhalation is the process of: A) Breathing out B) Breathing in ✅ C) Sweating D) Digestion Explanation: Inhalation draws air into the lungs using the diaphragm and intercostal muscles.

Which muscles help in breathing? A) Leg muscles B) Heart muscles C) Intercostal muscles ✅ D) Abdominal muscles Explanation: Intercostal muscles, located between the ribs, contract and expand the chest cavity during breathing.

The exchange of gases in alveoli occurs by: A) Active transport B) Diffusion ✅ C) Osmosis D) Filtration Explanation: Gases passively move from high to low concentration across thin alveolar membranes.

Which plant part has lenticels? A) Leaf B) Stem ✅ C) Flower D) Root Explanation: Lenticels are found on stems and allow gases to enter plant tissues.

Stomata are mostly present on the: A) Upper leaf surface B) Lower leaf surface ✅ C) Petiole D) Stem Explanation: The lower surface is shaded and reduces water loss, hence most stomata are located there.

Carbon dioxide is transported in blood mainly as: A) Gas B) Carbamino compounds C) Bicarbonate ions ✅ D) Carbonic acid Explanation: Most CO₂ dissolves in plasma and forms bicarbonate ions for efficient transport.

Spiracles are found in: A) Amphibians B) Reptiles C) Insects ✅ D) Birds Explanation: Insects breathe through spiracles, small openings on their body connected to tracheal tubes.

In breathing, the rib cage moves: A) Inward during inhalation B) Downward during inhalation C) Upward and outward during inhalation ✅ D) Upward and inward during exhalation Explanation: This movement expands the chest cavity, lowering pressure and allowing air in.

Bronchioles end in: A) Larynx B) Alveoli ✅ C) Trachea D) Bronchi Explanation: Bronchioles are small airways that terminate in alveoli where gas exchange takes place.

Which structure moistens and filters air? A) Pharynx B) Nasal cavity ✅ C) Larynx D) Bronchi Explanation: The nasal cavity has hairs and mucus that filter, moisten, and warm the air.

Which is a respiratory disorder? A) Diabetes B) Asthma ✅ C) Arthritis D) Anemia Explanation: Asthma is a chronic inflammatory disease of the airways causing wheezing and shortness of breath.

Emphysema affects: A) Liver B) Alveoli ✅ C) Kidneys D) Heart Explanation: Emphysema damages alveoli, reducing surface area for gas exchange and causing breathlessness.

Plants release oxygen during: A) Respiration B) Transpiration C) Photosynthesis ✅ D) Guttation Explanation: Photosynthesis converts CO₂ and water into glucose and oxygen, releasing O₂ as a by-product.

Main component of cigarette smoke causing damage is: A) Oxygen B) Tar ✅ C) Carbon D) Glucose Explanation: Tar coats alveoli, reducing their elasticity and increasing the risk of respiratory diseases.

Which is a passive process in respiration? A) Inhalation B) Exhalation ✅ C) Breathing D) Coughing Explanation: Exhalation occurs without muscle contraction as the diaphragm relaxes and air is pushed out.

Chapter 2: Homeostasis

Homeostasis refers to: A) Growth of an organism B) Maintenance of internal conditions ✅ C) Cell division D) Movement of limbs Explanation: Homeostasis is the body's ability to maintain a stable internal environment (e.g., temperature, water balance) despite external changes.
The organ responsible for filtering blood in humans is: A) Liver B) Lungs C) Kidney ✅ D) Heart Explanation: Kidneys remove waste products like urea from the blood, maintaining chemical balance.
The basic structural and functional unit of the kidney is: A) Neuron B) Alveolus C) Nephron ✅ D) Glomerulus Explanation: The nephron is the microscopic filtering unit of the kidney that forms urine.
Which part of nephron filters the blood? A) Collecting duct B) Bowman’s capsule ✅ C) Loop of Henle D) Distal tubule Explanation: Bowman’s capsule surrounds the glomerulus and begins the process of filtering blood.
Urea is formed in: A) Liver ✅ B) Kidney C) Intestine D) Bladder Explanation: The liver converts excess amino acids into urea, which is then excreted by the kidneys.
The fluid filtered by the glomerulus is called: A) Blood B) Filtrate ✅ C) Plasma D) Urine Explanation: Filtrate is the liquid that passes into the nephron tubule after blood is filtered by the glomerulus.
The loop of Henle is responsible for: A) Filtration B) Water reabsorption ✅ C) Secretion D) Protein digestion Explanation: The loop of Henle reabsorbs water, concentrating the urine and conserving body fluids.
Dialysis is a process used to: A) Filter blood artificially ✅ B) Pump blood C) Store oxygen D) Control temperature Explanation: Dialysis is a medical procedure for people with kidney failure to remove waste and excess fluids from the blood.
Which hormone regulates water reabsorption in kidneys? A) Insulin B) ADH ✅ C) Glucagon D) Adrenaline Explanation: ADH (Antidiuretic Hormone) increases water reabsorption in kidney tubules to regulate water balance.
The part of brain that controls homeostasis is: A) Cerebrum B) Cerebellum C) Medulla D) Hypothalamus ✅ Explanation: The hypothalamus controls body temperature, thirst, hunger, and hormone release, maintaining homeostasis.
The removal of metabolic waste is called: A) Excretion ✅ B) Digestion C) Respiration D) Circulation Explanation: Excretion removes metabolic wastes like urea and carbon dioxide from the body.
Sweating helps in: A) Digestion B) Blood clotting C) Temperature regulation ✅ D) Excretion of urea Explanation: Sweat evaporates from the skin, removing heat and helping to maintain body temperature.

Osmoregulation involves: A) Control of blood pressure B) Regulation of body temperature C) Maintenance of water and salt balance ✅ D) Control of sugar level Explanation: Osmoregulation ensures proper water and ion balance for cellular function and blood pressure.
Which disease occurs due to high sugar level in blood? A) Anemia B) Hepatitis C) Diabetes mellitus ✅ D) Kidney stone Explanation: Diabetes mellitus results from lack or improper use of insulin, causing high blood glucose.
Insulin is secreted by: A) Liver B) Pancreas ✅ C) Kidney D) Intestine Explanation: The pancreas secretes insulin, which regulates glucose uptake by cells.
Kidney stones are formed due to: A) Excess proteins B) Solid crystals in urine ✅ C) Dehydration D) High blood pressure Explanation: Kidney stones form when salts and minerals crystallize in concentrated urine.
The yellow color of urine is due to: A) Hemoglobin B) Uric acid C) Urochrome ✅ D) Glucose Explanation: Urochrome is a pigment produced from the breakdown of hemoglobin and gives urine its yellow color.
Glucose in urine indicates: A) Kidney failure B) Diabetes mellitus ✅ C) Liver damage D) High blood pressure Explanation: In diabetes, high blood glucose levels exceed the kidney’s reabsorption capacity, leading to glucose in urine.
Which structure carries urine from kidney to bladder? A) Urethra B) Nephron C) Ureter ✅ D) Loop of Henle Explanation: The ureter is a muscular tube that transports urine from the kidney to the bladder.
The bladder stores: A) Blood B) Sweat C) Urine ✅ D) Bile Explanation: The urinary bladder temporarily holds urine before it is expelled through the urethra.
Homeostasis in plants involves: A) Sweating B) Water balance ✅ C) Digestion D) Blood pressure Explanation: Plants regulate water levels via stomata and root activity to prevent wilting and maintain internal balance.
Which structure in plants helps in water regulation? A) Root hairs B) Xylem C) Stomata ✅ D) Phloem Explanation: Stomata open and close to regulate water loss and gas exchange.
Stomata close during: A) Day B) Rain C) Water scarcity ✅ D) Photosynthesis Explanation: To prevent dehydration, stomata close during drought or low water availability.
The condition of maintaining internal stability is: A) Mutation B) Equilibrium C) Homeostasis ✅ D) Circulation Explanation: Homeostasis involves the regulation of the body’s internal environment.
Which process helps in the removal of excess heat? A) Respiration B) Digestion C) Sweating ✅ D) Filtration Explanation: Sweating helps eliminate body heat through evaporation from the skin.
The tube that releases urine to the outside is: A) Ureter B) Urethra ✅ C) Nephron D) Loop of Henle Explanation: The urethra carries urine from the bladder to the external environment.
Which organ controls blood glucose level? A) Kidney B) Pancreas ✅ C) Liver D) Heart Explanation: The pancreas releases insulin and glucagon to regulate blood sugar levels.
What happens when ADH secretion is reduced? A) Water is conserved B) Urine becomes concentrated C) More urine is produced ✅ D) Blood sugar increases Explanation: Less ADH means less water is reabsorbed, leading to higher urine output.
Which disorder results in less or no insulin production? A) Hypothyroidism B) Diabetes mellitus ✅ C) Asthma D) Bronchitis Explanation: Type 1 diabetes results from destruction of insulin-producing cells in the pancreas.
The functional unit of excretion in humans is: A) Glomerulus B) Nephron ✅ C) Loop of Henle D) Collecting duct Explanation: The nephron filters blood, reabsorbs needed substances, and excretes waste as urine.

Chapter 3: Coordination and Control

Coordination in animals is controlled by: A) Circulatory system B) Respiratory system C) Nervous and endocrine systems ✅ D) Digestive system Explanation: Coordination in animals is carried out by the nervous system (for fast responses) and the endocrine system (for slower, long-term responses).
The basic unit of the nervous system is: A) Brain B) Neuron ✅ C) Spinal cord D) Nerve Explanation: A neuron (nerve cell) is the functional and structural unit of the nervous system, responsible for transmitting impulses.
The largest part of the human brain is: A) Cerebellum B) Medulla C) Cerebrum ✅ D) Thalamus Explanation: The cerebrum is the largest part of the brain and is involved in higher brain functions like thinking, memory, and voluntary movement.
Which part of the brain controls balance and coordination? A) Cerebrum B) Medulla C) Cerebellum ✅ D) Hypothalamus Explanation: The cerebellum helps maintain posture and balance and coordinates voluntary movements.
Reflex actions are controlled by the: A) Brain B) Spinal cord ✅ C) Heart D) Nerves Explanation: Reflex actions are quick, automatic responses controlled by the spinal cord for faster reaction.
The brain is protected by: A) Skin B) Skull ✅ C) Cartilage D) Muscle Explanation: The skull is a hard, bony structure that encases and protects the brain from physical damage.
Which part of the neuron receives impulses? A) Axon B) Myelin sheath C) Dendrites ✅ D) Synapse Explanation: Dendrites receive incoming signals from other neurons and carry them toward the cell body.
Synapse is a junction between: A) Neuron and muscle B) Two neurons ✅ C) Neuron and bone D) Brain and spinal cord Explanation: A synapse is a gap between two neurons where nerve impulses are chemically transmitted.
Which organ is known as the master gland? A) Adrenal gland B) Pancreas C) Pituitary gland ✅ D) Thyroid gland Explanation: The pituitary gland is called the master gland because it secretes hormones that regulate other endocrine glands.
Hormones are secreted by: A) Exocrine glands B) Endocrine glands ✅ C) Kidneys D) Lungs Explanation: Endocrine glands secrete hormones directly into the bloodstream to regulate body functions.
The hormone insulin controls: A) Blood pressure B) Glucose level ✅ C) Heart rate D) Body temperature Explanation: Insulin lowers blood glucose levels by helping cells absorb glucose.
Which gland produces adrenaline? A) Pituitary B) Adrenal ✅ C) Thyroid D) Pancreas Explanation: The adrenal glands secrete adrenaline, which prepares the body for "fight or flight" during stress.
The endocrine gland located in the neck is: A) Pituitary B) Thyroid ✅ C) Adrenal D) Pancreas Explanation: The thyroid gland is located in the neck and produces hormones that regulate metabolism.
The function of the myelin sheath is: A) Filter blood B) Store hormones C) Speed up nerve impulse transmission ✅ D) Produce enzymes Explanation: The myelin sheath insulates axons and increases the speed of nerve impulse conduction.
The peripheral nervous system consists of: A) Brain only B) Spinal cord only C) Nerves outside brain and spinal cord ✅ D) Endocrine glands Explanation: The peripheral nervous system includes all nerves that branch off from the brain and spinal cord.
The autonomic nervous system controls: A) Voluntary actions B) Involuntary actions ✅ C) Reflexes D) Thinking Explanation: The autonomic nervous system regulates involuntary functions such as heartbeat and digestion.
What is the function of cerebrum? A) Breathing B) Digestion C) Intelligence and memory ✅ D) Heartbeat regulation Explanation: The cerebrum controls voluntary actions and is responsible for thought, reasoning, and memory.
Which hormone controls growth? A) Insulin B) Growth hormone ✅ C) Adrenaline D) Estrogen Explanation: Growth hormone, secreted by the pituitary gland, stimulates body growth and cell reproduction.
The spinal cord is a part of: A) Central nervous system ✅ B) Peripheral nervous system C) Endocrine system D) Digestive system Explanation: The central nervous system consists of the brain and spinal cord, coordinating body functions.
Nervous system responses are: A) Slow and long-lasting B) Fast and short-term ✅ C) Random D) Delayed and permanent Explanation: Nervous responses happen rapidly and are short-lived, like a reflex or muscle movement.
Hormonal responses are: A) Quick and short-term B) Delayed and long-term ✅ C) Random and fast D) Voluntary Explanation: Hormones act slowly but have prolonged effects, such as growth and metabolism control.
Which gland helps regulate metabolism? A) Adrenal B) Pituitary C) Thyroid ✅ D) Pancreas Explanation: The thyroid gland produces hormones (like thyroxine) that regulate metabolism and energy usage.
The nervous system is made up of: A) Glands B) Organs C) Neurons ✅ D) Hormones Explanation: The basic building block of the nervous system is the neuron, which transmits electrical signals.
Coordination in plants is done by: A) Brain B) Hormones ✅ C) Neurons D) Muscles Explanation: Plants lack nerves and use hormones like auxin to coordinate responses to stimuli.
Tropic movements in plants are: A) Rapid and temporary B) Permanent and directional ✅ C) Random D) Involuntary Explanation: Tropic movements are slow, growth-based movements in response to directional stimuli (e.g., light or gravity).
The growth of plant towards light is: A) Geotropism B) Chemotropism C) Phototropism ✅ D) Hydrotropism Explanation: Phototropism is a plant's directional growth response to light, often bending towards it.
The movement of roots towards gravity is: A) Negative geotropism B) Positive geotropism ✅ C) Negative phototropism D) Hydrotropism Explanation: Roots grow downward due to gravity, showing a positive response to the stimulus.
Which hormone promotes growth in plants? A) Cytokinin B) Ethylene C) Auxin ✅ D) Insulin Explanation: Auxins promote cell elongation and are essential for directional growth responses.
In plants, the hormone responsible for cell division is: A) Cytokinin ✅ B) Auxin C) Ethylene D) Gibberellin Explanation: Cytokinins stimulate cell division and are vital for growth and tissue repair in plants.
Coordination is necessary for: A) Excretion B) Homeostasis ✅ C) Movement only D) Growth Explanation: Coordination integrates various physiological processes, ensuring homeostasis and survival.

Chapter 4: Support and Movement

Support and movement in animals are mainly provided by: A) Nervous system B) Muscular and skeletal systems ✅ C) Circulatory system D) Digestive system Explanation: The skeletal system provides structure and support, while muscles contract to produce movement.
The structural framework of the body is called: A) Skeleton ✅ B) Ligament C) Tendon D) Muscle Explanation: The skeleton is the internal framework that supports and shapes the body and protects organs.
The human skeleton consists of: A) 186 bones B) 206 bones ✅ C) 210 bones D) 200 bones Explanation: The adult human skeleton has 206 bones that support the body and allow movement.
The longest bone in the human body is: A) Humerus B) Tibia C) Femur ✅ D) Radius Explanation: The femur (thigh bone) is the longest and strongest bone in the human body.
Bones are connected to other bones by: A) Tendons B) Ligaments ✅ C) Muscles D) Cartilage Explanation: Ligaments are tough connective tissues that connect bone to bone at joints.
Muscles are connected to bones by: A) Ligaments B) Cartilage C) Tendons ✅ D) Joints Explanation: Tendons are fibrous tissues that attach muscles to bones and transmit the force needed for movement.
Which type of joint is present in the shoulder? A) Hinge B) Ball and socket ✅ C) Pivot D) Fixed Explanation: The shoulder joint is a ball and socket joint, allowing movement in all directions.
Which joint allows movement in one direction only? A) Ball and socket B) Hinge ✅ C) Gliding D) Saddle Explanation: Hinge joints (e.g., elbow, knee) allow movement like opening and closing a door — in one plane only.
The skull bone is an example of a: A) Hinge joint B) Fixed joint ✅ C) Pivot joint D) Movable joint Explanation: The skull bones are immovable and joined by sutures, making them fixed joints.
Cartilage is a: A) Fluid tissue B) Rigid bone C) Soft connective tissue ✅ D) Muscle fiber Explanation: Cartilage is a flexible connective tissue found in joints, nose, and ear.
Which part of the skeleton protects the brain? A) Rib cage B) Skull ✅ C) Vertebral column D) Pelvis Explanation: The skull encases and protects the brain from injury.
The backbone is made up of: A) 26 vertebrae ✅ B) 33 vertebrae C) 24 vertebrae D) 30 vertebrae Explanation: The adult vertebral column typically has 26 bones (including fused ones like the sacrum and coccyx).
The rib cage protects: A) Brain and spinal cord B) Heart and lungs ✅ C) Liver and pancreas D) Kidneys and intestines Explanation: The rib cage surrounds and protects vital organs like the heart and lungs.
Movement in plants is: A) Active only B) Passive only C) Both active and passive ✅ D) Not present Explanation: Plants show active movements like tropisms and passive movements like seed dispersal.
The human skeletal system has two parts: A) Upper and lower B) Skull and limbs C) Axial and appendicular ✅ D) Rib cage and limbs Explanation: The axial skeleton includes the skull and vertebral column; the appendicular skeleton includes limbs and girdles.
The bones of the limbs are part of: A) Axial skeleton B) Appendicular skeleton ✅ C) Central skeleton D) Peripheral skeleton Explanation: Limbs belong to the appendicular skeleton which allows movement.
Which bone is found in the upper arm? A) Femur B) Tibia C) Humerus ✅ D) Ulna Explanation: The humerus is the long bone in the upper arm that connects the shoulder to the elbow.
The disease in which bones become soft and weak due to calcium deficiency: A) Arthritis B) Osteoporosis ✅ C) Rickets D) Scurvy Explanation: Osteoporosis causes bones to become porous and weak, often due to calcium or vitamin D deficiency.
The joint between atlas and axis is a: A) Hinge joint B) Pivot joint ✅ C) Ball and socket joint D) Fixed joint Explanation: The pivot joint between the first two cervical vertebrae allows the head to rotate.
Voluntary muscles are also called: A) Smooth muscles B) Cardiac muscles C) Skeletal muscles ✅ D) Involuntary muscles Explanation: Skeletal muscles are under conscious control, thus called voluntary muscles.
Cardiac muscles are: A) Involuntary and striated ✅ B) Voluntary and striated C) Involuntary and non-striated D) Voluntary and smooth Explanation: Cardiac muscle, found only in the heart, is striated in appearance and contracts involuntarily.
Smooth muscles are found in: A) Heart B) Lungs C) Intestines ✅ D) Arms Explanation: Smooth muscles are involuntary and non-striated, found in internal organs like the stomach and intestines.
Which muscles work without conscious control? A) Skeletal muscles B) Smooth and cardiac muscles ✅ C) Striated muscles D) Voluntary muscles Explanation: Smooth and cardiac muscles contract automatically and are not under conscious control.
The ability of muscles to contract and relax helps in: A) Digestion B) Circulation C) Movement ✅ D) Respiration Explanation: Muscle contraction and relaxation are essential for body movement, posture, and locomotion.
Arthritis is a disease of the: A) Bones B) Muscles C) Joints ✅ D) Cartilage Explanation: Arthritis is inflammation of the joints, causing pain, swelling, and reduced mobility.
Movement in Mimosa plant is: A) Growth movement B) Tropic movement C) Nastic movement ✅ D) Active transport Explanation: Nastic movements are non-directional responses to stimuli, like Mimosa leaves folding when touched.
The bending of plant shoot towards light is: A) Geotropism B) Phototropism ✅ C) Hydrotropism D) Thigmotropism Explanation: Phototropism is the growth of a plant in response to light direction.
Bones are made hard by the presence of: A) Iron B) Calcium and phosphorus ✅ C) Potassium D) Magnesium Explanation: Calcium and phosphorus are minerals that provide hardness and strength to bones.
The part of the skeleton that includes ribs and sternum: A) Appendicular skeleton B) Axial skeleton ✅ C) Pelvic skeleton D) Shoulder girdle Explanation: The axial skeleton includes the skull, vertebral column, and rib cage.
A fracture is: A) Muscle tear B) Ligament break C) Bone break ✅ D) Joint dislocation Explanation: A fracture refers to a break in the continuity of a bone, caused by trauma or stress.

Chapter 5: Reproduction

Reproduction is the process of: A) Digestion of food B) Removal of waste C) Producing offspring ✅ D) Breathing Explanation: Reproduction ensures the continuity of species by creating new individuals.
The type of reproduction involving one parent only is: A) Sexual B) Asexual ✅ C) Fertilization D) Internal Explanation: Asexual reproduction involves a single parent and produces genetically identical offspring.
Binary fission is common in: A) Humans B) Amoeba ✅ C) Plants D) Insects Explanation: Amoeba reproduces asexually through binary fission, where the cell divides into two identical daughter cells.
Budding occurs in: A) Hydra ✅ B) Earthworm C) Paramecium D) Man Explanation: Hydra reproduces asexually by forming a small outgrowth (bud) that detaches to form a new individual.
Which of the following is an advantage of asexual reproduction? A) Slow process B) Genetic variation C) Quick reproduction ✅ D) Needs two parents Explanation: Asexual reproduction is fast and efficient, especially in favorable conditions.
Sexual reproduction involves: A) One parent B) No gametes C) Two parents ✅ D) Bud formation Explanation: Sexual reproduction involves fusion of male and female gametes from two parents.
Male gametes are called: A) Eggs B) Sperms ✅ C) Zygotes D) Embryos Explanation: Sperms are the male reproductive cells that fuse with an ovum during fertilization.
The female gamete in humans is: A) Sperm B) Ovum ✅ C) Zygote D) Larva Explanation: The ovum is the female gamete that combines with the sperm to form a zygote.
Fertilization is the fusion of: A) Two sperms B) Two eggs C) Sperm and egg ✅ D) Embryo and fetus Explanation: Fertilization is the union of a male and female gamete to form a zygote.
The organ that produces sperms is: A) Ovary B) Testes ✅ C) Uterus D) Penis Explanation: Testes are the male reproductive organs responsible for producing sperms and testosterone.
The female reproductive organ that produces eggs is: A) Uterus B) Vagina C) Ovary ✅ D) Fallopian tube Explanation: Ovaries produce and release eggs (ova) and also secrete female hormones.
The site of fertilization in females is: A) Ovary B) Uterus C) Vagina D) Fallopian tube ✅ Explanation: Fertilization usually occurs in the fallopian tube before the zygote travels to the uterus.
After fertilization, the zygote develops into: A) Ovum B) Sperm C) Embryo ✅ D) Egg Explanation: The zygote undergoes cell division and forms an embryo which implants in the uterus.
The baby develops in the: A) Fallopian tube B) Ovary C) Uterus ✅ D) Vagina Explanation: The uterus is the muscular organ where the embryo implants and develops into a fetus.
The union of gametes is called: A) Reproduction B) Fertilization ✅ C) Maturation D) Ovulation Explanation: Fertilization is the joining of sperm and egg, forming a zygote.
Which hormone regulates sperm production? A) Estrogen B) Progesterone C) Testosterone ✅ D) Insulin Explanation: Testosterone is the male sex hormone that stimulates sperm production and development of male features.
Which hormone is responsible for ovulation? A) FSH B) LH ✅ C) ADH D) Insulin Explanation: LH (Luteinizing Hormone) triggers the release of a mature egg from the ovary.
Menstruation occurs in: A) Males B) Females ✅ C) Both D) Children only Explanation: Menstruation is the monthly shedding of the uterine lining in females if fertilization does not occur.
External fertilization occurs in: A) Humans B) Birds C) Amphibians ✅ D) Mammals Explanation: In amphibians like frogs, fertilization happens outside the body, usually in water.
Internal fertilization is common in: A) Fishes B) Frogs C) Mammals ✅ D) Hydra Explanation: Mammals exhibit internal fertilization, where the sperm fertilizes the egg inside the female body.
Which structure carries sperm from testes? A) Urethra B) Vas deferens ✅ C) Epididymis D) Bladder Explanation: The vas deferens is the duct that transports sperm from the testes to the urethra.
The period from fertilization to birth is called: A) Puberty B) Gestation ✅ C) Menstruation D) Lactation Explanation: The gestation period is the time during which the embryo/fetus develops in the uterus until birth.
Identical twins are formed when: A) Two eggs are fertilized B) One zygote splits ✅ C) One sperm fertilizes two eggs D) Two sperms fertilize two eggs Explanation: Identical twins result from one fertilized egg splitting into two embryos with identical DNA.
Which structure provides nutrients to the fetus? A) Ovary B) Amnion C) Placenta ✅ D) Uterus Explanation: The placenta allows nutrient and gas exchange between the mother and fetus.
Asexual reproduction in plants can occur through: A) Seeds B) Flowers C) Vegetative parts ✅ D) Pollens Explanation: Asexual reproduction in plants can occur through stems, roots, or leaves (e.g., potato tubers).
Grafting is a method of: A) Sexual reproduction B) Artificial asexual reproduction ✅ C) Fertilization D) Natural selection Explanation: Grafting involves joining parts from two plants to grow as one and is used in agriculture.
The male part of a flower is called: A) Pistil B) Stigma C) Stamen ✅ D) Ovary Explanation: The stamen consists of the anther and filament and produces pollen grains (male gametes).
The transfer of pollen to stigma is: A) Fertilization B) Pollination ✅ C) Germination D) Ovulation Explanation: Pollination is the movement of pollen from the anther to the stigma for fertilization to occur.
Self-pollination occurs when: A) Pollen of one plant falls on another plant B) Pollen falls on same plant's stigma ✅ C) Fertilization occurs D) Pollen is sterile Explanation: In self-pollination, pollen from a flower lands on the stigma of the same flower or plant.
Cross-pollination increases: A) Uniformity B) Genetic variation ✅ C) Mutation D) Flower color Explanation: Cross-pollination involves two different plants and promotes genetic diversity in offspring.

Chapter 6: Inheritance

The passing of traits from parents to offspring is called: A) Evolution B) Reproduction C) Inheritance ✅ D) Mutation Explanation: Inheritance is the transfer of genetic traits from one generation to the next through genes.
The basic unit of inheritance is: A) Chromosome B) Gene ✅ C) DNA D) Trait Explanation: A gene is a segment of DNA that controls a specific trait and is passed from parent to offspring.
The father of genetics is: A) Charles Darwin B) Robert Hooke C) Gregor Mendel ✅ D) Watson Explanation: Gregor Mendel discovered the fundamental laws of inheritance through experiments on pea plants.
Mendel worked on: A) Tomatoes B) Maize C) Pea plants ✅ D) Beans Explanation: Mendel chose pea plants for his experiments due to their clear traits and ease of breeding.
Genes are located on: A) Ribosomes B) Chromosomes ✅ C) Cytoplasm D) Golgi bodies Explanation: Genes are specific sequences of DNA located on chromosomes within the nucleus of cells.
The physical expression of a trait is called: A) Genotype B) Phenotype ✅ C) Genome D) Chromosome Explanation: Phenotype refers to the observable characteristics (e.g., height, eye color) resulting from gene expression.
An organism with two identical alleles is: A) Heterozygous B) Homozygous ✅ C) Dominant D) Recessive Explanation: A homozygous organism has two of the same allele, either dominant or recessive.
Which pair of alleles is heterozygous? A) TT B) tt C) Tt ✅ D) TT Explanation: Heterozygous means having two different alleles, such as Tt (one dominant and one recessive).
A dominant trait is expressed in: A) Homozygous only B) Heterozygous only C) Both homozygous and heterozygous ✅ D) None Explanation: Dominant alleles are expressed whether the organism has one or two copies of the allele.
Recessive traits are expressed when: A) One dominant allele is present B) Both alleles are dominant C) Both alleles are recessive ✅ D) One allele is missing Explanation: A recessive trait appears only when both alleles are recessive.
The chromosome number in humans is: A) 46 ✅ B) 44 C) 23 D) 48 Explanation: Human cells normally contain 46 chromosomes — 23 pairs.
How many pairs of chromosomes are present in human cells? A) 20 B) 22 C) 23 ✅ D) 24 Explanation: Humans have 23 pairs of chromosomes, including one pair of sex chromosomes.
Sex chromosomes in human males are: A) XX B) XY ✅ C) YY D) X only Explanation: Males have one X and one Y chromosome.
Sex chromosomes in human females are: A) XY B) XX ✅ C) YY D) YX Explanation: Females have two X chromosomes.
A unit of DNA that carries instructions for a trait is: A) Protein B) Ribosome C) Gene ✅ D) Enzyme Explanation: Genes are DNA segments that code for proteins, influencing traits.
What is the shape of the DNA molecule? A) Single helix B) Circle C) Double helix ✅ D) Spiral cone Explanation: DNA has a twisted ladder-like structure known as a double helix.
DNA stands for: A) Deoxyribose acid B) Deoxyribonucleic acid ✅ C) Deoxynitrogen acid D) Deoxychromosome acid Explanation: DNA is composed of deoxyribose sugar, phosphate groups, and nitrogenous bases.
Mendel’s law of segregation states: A) Both alleles are inherited together B) Only one allele is expressed C) Alleles separate during gamete formation ✅ D) Genes are lost in offspring Explanation: The law of segregation states that allele pairs separate during gamete formation, so offspring receive one allele from each parent.
Which blood group is the universal donor? A) A B) B C) AB D) O ✅ Explanation: Blood group O lacks A and B antigens, so it can be donated to any group.
Which blood group is the universal recipient? A) A B) AB ✅ C) B D) O Explanation: AB blood group has both antigens and no antibodies, allowing it to receive any blood type.
Genotype of a person with blood group O is: A) IAIA B) IBIB C) IAIB D) ii ✅ Explanation: Blood group O has two recessive alleles (i), making the genotype ii.
The genetic disorder caused by abnormal hemoglobin: A) Diabetes B) Sickle cell anemia ✅ C) Asthma D) Hemophilia Explanation: Sickle cell anemia is a hereditary condition in which red blood cells become misshapen due to defective hemoglobin.
A sudden change in gene or chromosome is: A) Evolution B) Mutation ✅ C) Reproduction D) Variation Explanation: A mutation is a change in the DNA sequence that can affect gene function.
Who discovered the structure of DNA? A) Mendel and Darwin B) Watson and Crick ✅ C) Lamarck and Hooke D) Franklin and Mendel Explanation: Watson and Crick proposed the double helix model of DNA in 1953.
If a father has blood group A and mother has O, the child may have: A) Only A or O ✅ B) Only AB C) Only B D) Any group Explanation: The father's genotype may be AO and mother's is OO, so the child can be A or O.
A carrier of a recessive gene: A) Shows the trait B) Does not carry gene C) Has one dominant and one recessive allele ✅ D) Is always sick Explanation: Carriers have one normal allele and one mutated allele but do not show symptoms of the disorder.
Homozygous dominant genotype is: A) TT ✅ B) Tt C) tt D) T Explanation: Homozygous dominant means both alleles are dominant, e.g., TT.
Which of the following determines the sex of a child? A) X chromosome from mother B) Y chromosome from father ✅ C) X chromosome from father D) Autosomes Explanation: The sperm determines the child's sex. An X sperm results in a girl; a Y sperm results in a boy.
An example of a sex-linked disease: A) Cancer B) Tuberculosis C) Hemophilia ✅ D) Malaria Explanation: Hemophilia is a recessive disorder linked to the X chromosome and occurs more often in males.
Mendel’s work remained unnoticed for: A) 10 years B) 25 years C) 34 years ✅ D) 100 years Explanation: Mendel's work was rediscovered around 1900, 34 years after it was published.

Chapter 7: Man and His Environment

The surroundings in which an organism lives is called: A) Habitat B) Ecosystem C) Environment ✅ D) Community Explanation: The environment includes all biotic (living) and abiotic (non-living) factors that affect an organism's life.
The branch of biology that deals with the interaction between organisms and their environment is: A) Anatomy B) Genetics C) Ecology ✅ D) Physiology Explanation: Ecology studies the relationships of organisms with each other and with their physical surroundings.
All organisms of the same species living in an area form a: A) Population ✅ B) Community C) Ecosystem D) Biosphere Explanation: A population is a group of individuals of the same species living and interacting in a specific area.
A group of different populations living together is a: A) Community ✅ B) Habitat C) Biome D) Environment Explanation: A community consists of all the populations of different species that live and interact in the same area.
The largest ecosystem is the: A) Forest B) Pond C) Desert D) Biosphere ✅ Explanation: The biosphere includes all living organisms on Earth along with their physical environment.
An example of an abiotic component is: A) Plants B) Fungi C) Water ✅ D) Bacteria Explanation: Abiotic factors are non-living parts of the environment like air, water, soil, and sunlight.
Which of the following is a biotic component? A) Bacteria ✅ B) Temperature C) Soil D) Sunlight Explanation: Biotic components are living organisms such as plants, animals, fungi, and bacteria.
A place where an organism lives is called its: A) Habitat ✅ B) Ecosystem C) Community D) Niche Explanation: A habitat is the physical area or environment where an organism lives.
The role of an organism in its environment is called: A) Habitat B) Niche ✅ C) Ecosystem D) Territory Explanation: A niche includes an organism’s role in the ecosystem, including its diet, behavior, and interactions.
The main source of energy for ecosystems is: A) Wind B) Water C) Soil D) Sun ✅ Explanation: The Sun provides energy for producers (plants), which is passed through food chains.
Organisms that make their own food are called: A) Consumers B) Decomposers C) Producers ✅ D) Predators Explanation: Producers, such as green plants, make food via photosynthesis using sunlight.
Herbivores are: A) Meat eaters B) Plant and meat eaters C) Decomposers D) Plant eaters ✅ Explanation: Herbivores feed only on plant materials.
A food chain starts with: A) Consumer B) Decomposer C) Producer ✅ D) Carnivore Explanation: Producers are the first level in any food chain as they generate energy-rich food.
An example of a decomposer is: A) Cow B) Lion C) Grass D) Fungus ✅ Explanation: Decomposers break down dead organisms and recycle nutrients into the environment.
The pyramid of energy always shows: A) Increase in energy B) Same energy at each level C) Decrease in energy ✅ D) Energy production Explanation: Energy decreases at each trophic level due to energy loss as heat and movement.
Excessive cutting of trees is called: A) Reforestation B) Deforestation ✅ C) Afforestation D) Pollution Explanation: Deforestation is the removal of trees which leads to habitat loss and environmental imbalance.
Greenhouse gases include: A) Oxygen and nitrogen B) Carbon dioxide and methane ✅ C) Helium and neon D) Hydrogen and carbon Explanation: CO₂ and CH₄ trap heat in the Earth's atmosphere, contributing to global warming.
Acid rain is caused by: A) Water vapor B) Sulfur dioxide and nitrogen oxides ✅ C) Methane D) Ozone Explanation: These gases form acids in the atmosphere, which fall to Earth with rain.
The increase in Earth’s temperature is called: A) Ozone depletion B) Global warming ✅ C) Acidification D) Deforestation Explanation: Global warming refers to the rise in average global temperature due to increased greenhouse gases.
Which layer protects the Earth from UV rays? A) Troposphere B) Ionosphere C) Ozone layer ✅ D) Mesosphere Explanation: The ozone layer in the stratosphere absorbs most harmful ultraviolet radiation from the sun.
Which of the following is a renewable resource? A) Coal B) Solar energy ✅ C) Natural gas D) Petroleum Explanation: Renewable resources are replenished naturally, like sunlight and wind.
Which human activity contributes most to air pollution? A) Tree planting B) Burning fossil fuels ✅ C) Grazing D) Composting Explanation: Combustion of fossil fuels releases pollutants like CO₂ and SO₂ into the air.
The natural resource that can be recycled is: A) Coal B) Paper ✅ C) Petroleum D) Gas Explanation: Paper can be collected and reprocessed into new paper products, reducing deforestation.
Which of the following is a biodegradable pollutant? A) Plastic B) Glass C) Vegetable waste ✅ D) Metal cans Explanation: Biodegradable substances like food and plant waste decompose naturally by microorganisms.
The main cause of water pollution is: A) Wind B) Industrial waste ✅ C) Solar radiation D) Tree plantation Explanation: Waste from factories, when discharged into water bodies, contaminates water and harms aquatic life.
A method to conserve water is: A) Deforestation B) Rainwater harvesting ✅ C) Over-irrigation D) Building dams only Explanation: Rainwater harvesting collects and stores rainwater for reuse, reducing dependence on groundwater.
Which of these is a non-renewable resource? A) Water B) Sunlight C) Coal ✅ D) Air Explanation: Coal takes millions of years to form and cannot be replenished within a human timescale.
Soil erosion is prevented by: A) Overgrazing B) Afforestation ✅ C) Mining D) Industrialization Explanation: Planting trees helps bind the soil and reduce erosion caused by wind and water.
The best way to manage solid waste is: A) Burning B) Reduce, reuse, recycle ✅ C) Dumping in water D) Burying in forests Explanation: The 3Rs reduce waste volume and environmental impact by minimizing use and promoting reuse/recycling.
Environmental pollution affects: A) Only humans B) Only animals C) Only plants D) All living organisms ✅ Explanation: Pollution harms the health and survival of all life forms and disrupts ecosystems.

Chapter 8: Biotechnology

Biotechnology is the use of living organisms to: A) Create pollution B) Make tools C) Produce useful products ✅ D) Destroy nature Explanation: Biotechnology uses biological systems or organisms to develop products like medicine, food, and enzymes.
The father of biotechnology is considered to be: A) Charles Darwin B) Karl Ereky ✅ C) Louis Pasteur D) Gregor Mendel Explanation: Karl Ereky coined the term "biotechnology" in 1919 and is known for early applications in biological industries.
Which of the following is used in biotechnology? A) Robots B) Satellites C) Microorganisms ✅ D) Fossils Explanation: Microorganisms such as bacteria and yeast are used in fermentation, drug production, and genetic engineering.
The branch of biotechnology that deals with medicine is: A) Green biotechnology B) Blue biotechnology C) Red biotechnology ✅ D) White biotechnology Explanation: Red biotechnology is concerned with medical processes like producing vaccines and antibiotics.
Fermentation is a process carried out by: A) Viruses B) Yeast and bacteria ✅ C) Algae D) Worms Explanation: Yeast and bacteria convert sugars into products like alcohol, gases, and acids during fermentation.
Which gas is produced during fermentation by yeast? A) Oxygen B) Carbon dioxide ✅ C) Hydrogen D) Methane Explanation: Yeast produces carbon dioxide and alcohol when it ferments sugars in anaerobic conditions.
Bread rises due to the production of: A) Water B) Alcohol C) Carbon dioxide ✅ D) Glucose Explanation: CO₂ produced by yeast causes the dough to expand and rise, creating soft bread texture.
Penicillin is obtained from a: A) Bacterium B) Alga C) Fungus ✅ D) Plant Explanation: Penicillin is an antibiotic first extracted from the fungus Penicillium notatum.
Who discovered penicillin? A) Louis Pasteur B) Robert Koch C) Alexander Fleming ✅ D) Watson and Crick Explanation: Fleming discovered penicillin in 1928, revolutionizing the treatment of bacterial infections.
Which of the following is an antibiotic? A) Insulin B) Glucose C) Penicillin ✅ D) Amylase Explanation: Penicillin kills or inhibits bacterial growth, making it an effective antibiotic.
Genetic engineering involves manipulation of: A) RNA B) Enzymes C) DNA ✅ D) Hormones Explanation: Genetic engineering modifies an organism’s DNA to introduce new traits or produce useful substances.
A genetically modified organism (GMO) is one that has: A) No genes B) Damaged DNA C) Foreign genes introduced ✅ D) No function Explanation: GMOs have had specific genes inserted into their genome to give them desired traits.
Insulin is now produced using: A) Human pancreas B) Genetically modified bacteria ✅ C) Yeast D) Fungi Explanation: Bacteria like E. coli are genetically modified to produce human insulin for diabetic patients.
The process of inserting genes into organisms is called: A) Replication B) Translation C) Gene splicing ✅ D) Digestion Explanation: Gene splicing is a technique in which DNA from different sources is joined together.
Biofertilizers contain: A) Pesticides B) Chemicals C) Living microorganisms ✅ D) Hormones Explanation: Biofertilizers use microbes like Rhizobium to enhance soil fertility by fixing atmospheric nitrogen.
Tissue culture is a technique to: A) Destroy cells B) Stop growth C) Grow new plants from a few cells ✅ D) Kill bacteria Explanation: In tissue culture, a few plant cells are grown in nutrient medium to develop into a complete plant.
Vaccines are used to: A) Treat diseases B) Prevent diseases ✅ C) Digest food D) Kill insects Explanation: Vaccines stimulate the immune system to recognize and fight pathogens before they cause disease.
The first genetically engineered insulin was called: A) Biolin B) Medicin C) Humulin ✅ D) Vaccinex Explanation: Humulin was the first synthetic human insulin made using recombinant DNA technology
Which organism is commonly used in genetic engineering? A) Bacteria ✅ B) Algae C) Earthworms D) Viruses Explanation: Bacteria like E. coli are easy to manipulate and reproduce quickly, making them ideal for gene insertion.
Which enzyme is used to cut DNA in biotechnology? A) Amylase B) Protease C) Restriction enzyme ✅ D) Ligase Explanation: Restriction enzymes act like molecular scissors, cutting DNA at specific sequences.
Which is a product of biotechnology in food industry? A) Bread B) Cheese C) Both A and B ✅ D) None Explanation: Biotechnology plays a role in fermenting yeast in bread and bacteria in cheese production.
Enzymes in washing powders are used to: A) Stain clothes B) Change color C) Break down stains ✅ D) Harden fabrics Explanation: Enzymes like proteases and lipases break down food and oil stains for better cleaning.
DNA fingerprinting is useful in: A) Cooking B) Identifying individuals ✅ C) Blood donation D) Cloning Explanation: DNA fingerprinting is used in forensics and paternity tests to match DNA samples.
Biotechnology helps in: A) Soil erosion B) Disease control ✅ C) Air pollution D) Radiation increase Explanation: It helps produce medicines and vaccines, improving health and disease prevention.
Biofuel is a fuel made from: A) Coal B) Biomass ✅ C) Diesel D) Natural gas Explanation: Biofuels are renewable fuels derived from organic materials like plants and waste.
The organism used in alcohol production is: A) Bacteria B) Mold C) Yeast ✅ D) Algae Explanation: Yeast ferments sugars to produce ethanol (alcohol), widely used in beverages and fuel.
Biogas mainly contains: A) Carbon dioxide B) Oxygen C) Methane ✅ D) Nitrogen Explanation: Biogas is mostly methane and is produced by the anaerobic decomposition of organic matter.
Which is not a product of biotechnology? A) Cheese B) Bread C) Plastic ✅ D) Penicillin Explanation: Plastic is a synthetic petroleum-based product, not produced using biotechnology.
Which of these is used in tissue culture? A) Stones B) Mature plant C) Small piece of plant tissue ✅ D) Soil Explanation: A small piece of plant tissue (explants) is placed in a sterile nutrient medium to grow new plants.
Biotechnology helps in improving: A) Weather B) Crop yield ✅ C) Fossil fuel use D) Volcanoes Explanation: By developing disease-resistant and high-yield varieties, biotechnology boosts agricultural productivity.

Chapter 9: Pharmacology

Pharmacology is the study of: A) Plants B) Diseases C) Drugs and their effects ✅ D) Hormones Explanation: Pharmacology deals with how drugs interact with biological systems to treat or prevent diseases.
The science of preparing and dispensing drugs is called: A) Pathology B) Pharmacy ✅ C) Neurology D) Toxicology Explanation: Pharmacy involves the formulation, preparation, and distribution of medications.
The branch of pharmacology dealing with harmful effects of drugs is: A) Virology B) Toxicology ✅ C) Immunology D) Pharmacognosy Explanation: Toxicology studies the adverse effects of chemicals and drugs on living organisms.
The dosage of a drug depends on: A) Weather B) Age and weight ✅ C) Blood group D) Temperature Explanation: Dosage varies depending on individual characteristics like age, weight, and medical condition.
Which of the following is an antibiotic? A) Aspirin B) Penicillin ✅ C) Paracetamol D) Insulin Explanation: Penicillin is a drug that kills or inhibits the growth of bacteria.
Drugs are tested on: A) Healthy humans only B) Animals and humans ✅ C) Air and water D) Soil Explanation: Drugs undergo pre-clinical testing on animals and clinical trials on humans for safety and effectiveness.
Vaccine is a substance used to: A) Treat disease B) Prevent disease ✅ C) Cure injury D) Build muscle Explanation: Vaccines stimulate the immune system to protect against specific infectious diseases.
Oral drugs are taken through: A) Injection B) Mouth ✅ C) Skin D) Nose Explanation: Oral drugs are swallowed and absorbed through the digestive system.
The method of injecting drug into a vein is called: A) Intramuscular B) Subcutaneous C) Intravenous ✅ D) Oral Explanation: Intravenous (IV) administration delivers drugs directly into the bloodstream for rapid action.
Which of the following is used to reduce pain? A) Antibiotics B) Analgesics ✅ C) Vaccines D) Hormones Explanation: Analgesics like aspirin and paracetamol relieve pain without causing loss of consciousness.
Drugs that reduce fever are called: A) Analgesics B) Antipyretics ✅ C) Antibiotics D) Narcotics Explanation: Antipyretics lower body temperature in case of fever.
The term "addiction" refers to: A) Physical or psychological dependence on a drug ✅ B) Cure of disease C) Recovery process D) Sleep aid Explanation: Addiction is a condition where a person cannot stop using a substance despite harmful effects.
Heroin is classified as a: A) Stimulant B) Antipyretic C) Narcotic ✅ D) Hallucinogen Explanation: Heroin is a highly addictive narcotic that suppresses the central nervous system.
A drug that stimulates the brain is: A) Alcohol B) Caffeine ✅ C) Morphine D) Diazepam Explanation: Caffeine is a stimulant that temporarily increases alertness and energy.
A drug that slows down brain activity is a: A) Depressant ✅ B) Stimulant C) Hallucinogen D) Vaccine Explanation: Depressants reduce neural activity and are used in calming or sleep-inducing medications.
Tobacco contains: A) Cocaine B) Nicotine ✅ C) Heroin D) Cannabis Explanation: Nicotine is a stimulant found in tobacco that causes addiction and health issues.
Excessive use of sleeping pills can lead to: A) Alertness B) Addiction ✅ C) Weight gain D) Increased strength Explanation: Misuse of sedatives or tranquilizers can cause dependency and overdose.
Which drug is used to treat bacterial infections? A) Aspirin B) Penicillin ✅ C) Morphine D) Diazepam Explanation: Penicillin is an antibiotic effective against bacterial infections.
Aspirin is used as a: A) Antibiotic B) Painkiller ✅ C) Antiseptic D) Hormone Explanation: Aspirin is a commonly used analgesic and antipyretic drug.
Alcohol affects the: A) Digestive system B) Nervous system ✅ C) Skeletal system D) Integumentary system Explanation: Alcohol is a depressant that slows down brain and nerve function.
The main function of an antacid is to: A) Cure cancer B) Neutralize stomach acid ✅ C) Lower blood sugar D) Kill viruses Explanation: Antacids relieve indigestion by neutralizing excess stomach acid.
Drug abuse is: A) Using drugs for treatment B) Misuse of drugs for pleasure ✅ C) Medical prescription D) Taking vitamins Explanation: Drug abuse is the use of legal or illegal substances for non-medical purposes.
The most commonly abused legal drug is: A) Heroin B) Alcohol ✅ C) Cocaine D) LSD Explanation: Alcohol is legally available but is frequently misused, leading to addiction and health issues.
Withdrawal symptoms occur when: A) Drug use is suddenly stopped ✅ B) Food is not taken C) Oxygen is low D) Sleep is increased Explanation: People addicted to drugs may suffer physical or mental symptoms when they stop using the substance.
Methamphetamine is a: A) Pain reliever B) Sedative C) Stimulant ✅ D) Vaccine Explanation: Methamphetamine is a powerful stimulant that increases activity in the brain.
Inhalants are substances that are: A) Swallowed B) Breathed in for mind-altering effects ✅ C) Injected D) Used as food Explanation: Inhalants are vapors of substances like glue or spray paint that are sniffed for a high.
Narcotics are used medically to: A) Increase weight B) Relieve severe pain ✅ C) Treat infections D) Reduce fever Explanation: Narcotics like morphine are prescribed for extreme pain, especially post-surgery.
Which organ is most affected by alcohol abuse? A) Heart B) Brain C) Liver ✅ D) Kidneys Explanation: The liver metabolizes alcohol and suffers damage with excessive, long-term use (e.g., cirrhosis).
Which of the following is a hallucinogen? A) Nicotine B) LSD ✅ C) Aspirin D) Insulin Explanation: LSD is a drug that causes hallucinations, altering perception and mood.
The best way to prevent drug abuse is: A) Isolation B) Punishment C) Awareness and education ✅ D) Delay of treatment Explanation: Education about the dangers of drug misuse helps people make informed, healthy choices.

Chemistry

Chapter 1: Chemical Equilibrium

Which of the following is a reversible reaction? A) Combustion of fuel B) Photosynthesis C) Formation of ammonia from N₂ and H₂ D) Decomposition of calcium carbonate Answer: C Explanation: The reaction N₂ + 3H₂ ⇌ 2NH₃ is a classic example of a reversible reaction where products can reconvert into reactants under suitable conditions.
At chemical equilibrium: A) All reactants are converted to products B) Reaction stops C) Forward and reverse reactions occur at the same rate D) Concentrations of all substances become zero Answer: C Explanation: At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction, though both continue to occur dynamically.
Which term best describes the state when forward and reverse reactions continue at equal rates? A) Static B) Kinetic C) Dynamic equilibrium D) Mass action Answer: C Explanation: Dynamic equilibrium means the system is active, with ongoing reactions in both directions, but no net change in concentrations.
The law of mass action was proposed by: A) Arrhenius B) Le Chatelier C) Guldberg and Waage D) Dalton Answer: C Explanation: Guldberg and Waage formulated the law stating that the rate of a chemical reaction is proportional to the product of the concentrations of reactants.
In the equilibrium expression, the square brackets represent: A) Pressure B) Temperature C) Concentration D) Molar mass Answer: C Explanation: Square brackets denote the molar concentrations of substances in mol/L.
The equilibrium constant (Kc) for a reaction depends on: A) Catalyst B) Concentration C) Temperature D) Pressure Answer: C Explanation: Kc is affected only by temperature; it remains unchanged with concentration, pressure, or catalysts.
For the reaction N₂ + 3H₂ ⇌ 2NH₃, the expression for Kc is: A) [N₂][H₂]³ / [NH₃]² B) [NH₃]² / [N₂][H₂]³ C) [NH₃] / [N₂][H₂] D) [H₂][NH₃] / [N₂] Answer: B Explanation: The equilibrium constant expression is derived from the balanced equation using product concentrations over reactant concentrations, each raised to the power of their coefficients.
If Kc >> 1, it indicates: A) More reactants B) Equal reactants and products C) More products D) Reaction not possible Answer: C Explanation: A large Kc value means the concentration of products is much greater than that of reactants at equilibrium.
A catalyst affects equilibrium by: A) Shifting position B) Increasing product concentration C) Speeding up reaction only D) Increasing reactant concentration Answer: C Explanation: A catalyst speeds up both forward and reverse reactions equally without affecting the position of equilibrium.

Which condition must be met for equilibrium to be established? A) Constant pressure B) Closed system C) Increasing temperature D) Open system Answer: B Explanation: A closed system ensures that no reactants or products are lost, which is essential for achieving equilibrium.
At equilibrium, the concentration of products and reactants is: A) Zero B) Constant C) Increasing D) Decreasing Answer: B Explanation: At equilibrium, although the reactions continue, the concentrations of reactants and products remain constant over time.
If Qc < Kc, the system: A) Is at equilibrium B) Will shift forward C) Will shift backward D) Stops reacting Answer: B Explanation: If Qc (reaction quotient) is less than Kc (equilibrium constant), more products need to form, so the reaction shifts forward.
In the equilibrium constant, solids and liquids are: A) Always included B) Sometimes included C) Never included D) Doubled Answer: C Explanation: Pure solids and liquids are not included in the equilibrium expression because their concentrations remain constant.
Equilibrium is best studied in: A) Closed beaker B) Open flask C) Sealed container D) Funnel Answer: C Explanation: A sealed container ensures a closed system where no reactants or products escape, allowing equilibrium to be studied accurately.
Dynamic equilibrium means: A) Only products are present B) No reaction occurs C) Both reactions occur continuously D) Forward reaction is stopped Answer: C Explanation: Dynamic equilibrium refers to the ongoing and simultaneous forward and reverse reactions at equal rates.
Le Chatelier’s Principle predicts: A) Temperature of reaction B) Pressure of system C) Effect of change on equilibrium D) None of these Answer: C Explanation: This principle states that if a system at equilibrium is disturbed, it will shift to counteract the disturbance.
The units of Kc depend on: A) Type of reaction B) Number of moles C) Temperature D) Pressure Answer: B Explanation: The units of Kc vary with the balanced chemical equation and depend on the difference in moles of products and reactants.
In a reaction, if Kc = 1, it means: A) Reactants dominate B) Products dominate C) Forward reaction only D) Reactants ≈ Products Answer: D Explanation: A Kc value of 1 indicates that the concentrations of products and reactants are nearly equal at equilibrium.
Which is an example of a system in equilibrium? A) Iron rusting B) Boiling water C) CO₂ ⇌ CO + ½O₂ D) Burning candle Answer: C Explanation: The reaction between CO₂, CO, and O₂ is reversible and can reach equilibrium under suitable conditions.
When Kc is very small, the reaction: A) Favors reactants B) Favors products C) Goes to completion D) Is very fast Answer: A Explanation: A small Kc indicates that very little product is formed; hence, the equilibrium lies toward the reactants.
Effect of increasing concentration on equilibrium: A) No effect B) Shifts to opposite side C) Stops reaction D) Reaches faster Answer: B Explanation: According to Le Chatelier’s Principle, increasing the concentration of a substance shifts the equilibrium to oppose the change.
Which quantity is equal in forward and reverse reactions at equilibrium? A) Energy B) Moles C) Rate D) Time Answer: C Explanation: At equilibrium, the forward and reverse reaction rates are equal, even though the concentrations might differ.
What happens to equilibrium when temperature increases in an exothermic reaction? A) Shifts forward B) Shifts backward C) No change D) Stops Answer: B Explanation: In exothermic reactions, heat acts like a product. Increasing temperature shifts the equilibrium backward to absorb the excess heat.
Which is not a characteristic of equilibrium? A) Closed system B) Constant temperature C) Change in pressure D) Opposite reactions at same rate Answer: C Explanation: A change in pressure can disturb equilibrium, so it's not a characteristic of a system already at equilibrium.
Kc = [products]ⁿ / [reactants]ᵐ is based on: A) Atomic structure B) Periodic table C) Law of mass action D) Kinetic theory Answer: C Explanation: This mathematical expression is derived from the law of mass action which governs how equilibrium concentrations relate.
In endothermic reactions, increasing temperature shifts equilibrium: A) Backward B) Forward C) Stops it D) No effect Answer: B Explanation: For endothermic reactions, heat is absorbed; increasing temperature favors the forward direction.
Which factor does not affect Kc value? A) Pressure B) Temperature C) Catalyst D) Volume Answer: C Explanation: Catalysts only affect the speed at which equilibrium is reached but do not alter the equilibrium constant.
When forward and reverse reactions have equal rates, it is: A) Static equilibrium B) Dynamic equilibrium C) Physical change D) No reaction Answer: B Explanation: In dynamic equilibrium, both reactions occur at the same rate, maintaining stable concentrations.
Which of the following is not required for equilibrium? A) Closed system B) Reversible reaction C) Continuous change D) Catalyst Answer: D Explanation: While catalysts speed up reactions, they are not required for equilibrium to be established or maintained.
Equilibrium constant expression includes only: A) Gases and aqueous solutions B) Solids and gases C) All reactants D) All substances Answer: A Explanation: Only gases and aqueous solutions appear in the equilibrium expression; solids and pure liquids are excluded.

Chapter 2: Acids, Bases and Salts

Which of the following is a characteristic of acids? A) Bitter taste B) Soapy feel C) Turns blue litmus red D) Turns red litmus blue Answer: C Explanation: Acids turn blue litmus paper red due to the presence of hydrogen ions (H⁺).
A base is a substance that: A) Donates protons B) Accepts electrons C) Accepts protons D) Donates neutrons Answer: C Explanation: According to the Bronsted-Lowry theory, a base is a proton (H⁺) acceptor.
The pH of a neutral solution is: A) 0 B) 7 C) 14 D) 1 Answer: B Explanation: A neutral solution, like pure water, has a pH of 7, indicating equal H⁺ and OH⁻ ions.
Which of the following is a strong acid? A) HCl B) CH₃COOH C) H₂CO₃ D) H₃PO₄ Answer: A Explanation: HCl is a strong acid because it completely ionizes in water.
An example of a weak base is: A) NaOH B) KOH C) NH₄OH D) Ca(OH)₂ Answer: C Explanation: Ammonium hydroxide (NH₄OH) partially ionizes in water, making it a weak base.
Bronsted-Lowry acid is a substance that: A) Donates electrons B) Accepts protons C) Donates protons D) Accepts electrons Answer: C Explanation: A Bronsted-Lowry acid donates protons (H⁺) during a chemical reaction.
Which pair is a conjugate acid-base pair? A) HCl / Cl⁻ B) H₂O / O₂ C) H₂ / H₂O D) NaOH / Na⁺ Answer: A Explanation: HCl donates a proton to form Cl⁻, making them a conjugate acid-base pair.
Lewis base is a substance that: A) Donates a proton B) Accepts a proton C) Donates an electron pair D) Accepts an electron pair Answer: C Explanation: A Lewis base donates a lone pair of electrons to form a bond.
In water, acids produce: A) OH⁻ ions B) Na⁺ ions C) H⁺ ions D) Cl⁻ ions Answer: C Explanation: Acids release H⁺ ions when dissolved in water.
pH + pOH = ? A) 7 B) 10 C) 12 D) 14 Answer: D Explanation: The sum of pH and pOH is always 14 at 25°C (standard temperature).
If pH is less than 7, the solution is: A) Basic B) Neutral C) Acidic D) None of these Answer: C Explanation: A pH below 7 indicates an acidic solution.
Which of the following is an amphoteric substance? A) HCl B) NaOH C) H₂O D) NH₄OH Answer: C Explanation: Water (H₂O) can act as both an acid and a base, making it amphoteric.
A salt is formed by the reaction of: A) Acid with acid B) Base with base C) Acid with base D) Salt with acid Answer: C Explanation: A neutralization reaction between an acid and a base forms salt and water.
Neutralization reaction results in: A) Acid B) Base C) Salt and water D) Acid and gas Answer: C Explanation: Neutralization always produces a salt and water as products.
Buffer solution resists change in: A) Volume B) pH C) Temperature D) Pressure Answer: B Explanation: A buffer maintains a nearly constant pH by neutralizing small additions of acids or bases.
Which one is a basic salt? A) NaCl B) CH₃COONa C) NH₄Cl D) Na₂CO₃ Answer: D Explanation: Sodium carbonate (Na₂CO₃) is a basic salt formed from a strong base and weak acid.
Which is an acidic salt? A) Na₂SO₄ B) CH₃COONa C) NaHCO₃ D) NH₄Cl Answer: D Explanation: NH₄Cl is formed from a strong acid (HCl) and weak base (NH₃), making it acidic.
pH of strong base is usually: A) < 7 B) = 7 C) > 7 D) 0 Answer: C Explanation: A strong base fully ionizes in water and has a pH significantly above 7.
Litmus is an example of: A) Acid B) Salt C) Indicator D) Base Answer: C Explanation: Litmus is a pH indicator used to detect acidity or basicity.
HCl reacts with NaOH to form: A) H₂ and NaCl B) NaCl and water C) NaOH and Cl₂ D) H₂O and Na Answer: B Explanation: This is a typical neutralization reaction yielding salt (NaCl) and water (H₂O).
Which of the following is a weak acid? A) HCl B) HNO₃ C) H₂SO₄ D) CH₃COOH Answer: D Explanation: Acetic acid (CH₃COOH) only partially ionizes in water, making it a weak acid.
Conjugate base of H₂SO₄ is: A) SO₄²⁻ B) HSO₄⁻ C) H₃SO₄⁺ D) HSO₄²⁻ Answer: B Explanation: When H₂SO₄ loses one proton, it forms HSO₄⁻, which is the conjugate base.
Lewis acid is: A) Electron donor B) Electron acceptor C) Proton donor D) Proton acceptor Answer: B Explanation: A Lewis acid accepts an electron pair to form a coordinate bond.
The basicity of H₂SO₄ is: A) 1 B) 2 C) 3 D) 4 Answer: B Explanation: H₂SO₄ has two replaceable hydrogen ions (protons), so its basicity is 2.
Which of the following is a diprotic acid? A) HCl B) HNO₃ C) H₂SO₄ D) CH₃COOH Answer: C Explanation: A diprotic acid like H₂SO₄ can donate two protons per molecule.
A substance that changes color with pH is: A) Salt B) Indicator C) Solvent D) Electrolyte Answer: B Explanation: Indicators are chemicals that change color depending on the pH of the solution.
Amphoteric substances react with: A) Acids only B) Bases only C) Both acids and bases D) Neither acids nor bases Answer: C Explanation: Amphoteric substances like water or aluminum hydroxide can react with both acids and bases.
Acid rain is caused by: A) NaCl B) SO₂ and NO₂ C) CO₂ D) O₂ Answer: B Explanation: SO₂ and NO₂ dissolve in rainwater to form sulfuric and nitric acids, causing acid rain.
In a buffer solution, the weak acid is accompanied by: A) Strong base B) Weak base C) Its salt D) Another acid Answer: C Explanation: A buffer contains a weak acid and its conjugate base (salt) to resist pH changes.
The pH value of lemon juice is likely to be: A) Around 2 B) Around 5 C) Around 7 D) Around 9 Answer: A Explanation: Lemon juice is highly acidic due to citric acid, and has a pH around 2.

Chapter 3: Organic Chemistry

Which element is the backbone of organic compounds? A) Oxygen B) Hydrogen C) Nitrogen D) Carbon Answer: D Explanation: Organic compounds are based on carbon because it can form four covalent bonds and long chains or rings.
The ability of carbon to form long chains is called: A) Combustion B) Polymerization C) Catenation D) Saturation Answer: C Explanation: Catenation is the property of carbon to form long chains or rings with other carbon atoms.
Which is not a hydrocarbon? A) CH₄ B) C₂H₆ C) CCl₄ D) C₂H₂ Answer: C Explanation: CCl₄ contains carbon and chlorine, not just hydrogen and carbon, so it is not a hydrocarbon.
Which of the following is a saturated hydrocarbon? A) C₂H₂ B) C₂H₄ C) C₂H₆ D) C₆H₆ Answer: C Explanation: Saturated hydrocarbons (alkanes) have only single bonds. C₂H₆ (ethane) is an alkane.
Which of the following is an alkyne? A) C₂H₆ B) C₂H₄ C) C₂H₂ D) CH₃OH Answer: C Explanation: Alkynes contain a triple bond; C₂H₂ (ethyne) is the simplest alkyne.
The general formula for alkanes is: A) CnH₂n B) CnH₂n+2 C) CnH₂n−2 D) CnH₂nO Answer: B Explanation: Alkanes have the general formula CnH₂n+2, indicating saturation (all single bonds).
Alkenes contain: A) Single bonds only B) One triple bond C) One double bond D) Two triple bonds Answer: C Explanation: Alkenes are unsaturated hydrocarbons with at least one double bond.
Benzene is an example of: A) Alkane B) Alkyne C) Aromatic compound D) Alcohol Answer: C Explanation: Benzene is an aromatic compound with a ring structure and delocalized electrons.
Which compound is an alcohol? A) CH₄ B) CH₃OH C) C₂H₄ D) CCl₄ Answer: B Explanation: CH₃OH (methanol) contains the –OH (hydroxyl) functional group, making it an alcohol.
Functional group in alcohol is: A) –COOH B) –OH C) –CHO D) –CO Answer: B Explanation: The –OH group is the functional group characteristic of alcohols.
The simplest alkyne is: A) Ethene B) Ethyne C) Methane D) Propane Answer: B Explanation: Ethyne (C₂H₂) is the simplest alkyne, having a triple bond between carbon atoms.
Which functional group is present in carboxylic acids? A) –OH B) –COOH C) –CHO D) –CO Answer: B Explanation: Carboxylic acids contain the –COOH group, which gives acidic properties.
Which is the condensed formula of ethane? A) C₂H₄ B) CH₃–CH₃ C) CH₂=CH₂ D) C₂H₂ Answer: B Explanation: Ethane has two carbon atoms connected by a single bond, each bonded to three hydrogen atoms.
Methanoic acid is also known as: A) Formic acid B) Acetic acid C) Citric acid D) Tartaric acid Answer: A Explanation: Methanoic acid is the simplest carboxylic acid and is commonly called formic acid.
Which is a homologous series? A) Series with same boiling points B) Compounds with same physical state C) Series with same functional group and similar chemical properties D) All organic compounds Answer: C Explanation: Homologous series are families of organic compounds with the same functional group and a general formula.
The general formula of alkenes is: A) CnH₂n+2 B) CnH₂n C) CnH₂n−2 D) CnH₂n+1 Answer: B Explanation: Alkenes follow the general formula CnH₂n, indicating a double bond.
Ethanol is commonly used in: A) Soap B) Vinegar C) Alcoholic drinks D) Plastic Answer: C Explanation: Ethanol is the type of alcohol found in alcoholic beverages.
Esterification is a reaction between: A) Acid and base B) Alcohol and acid C) Alkane and alcohol D) Base and salt Answer: B Explanation: Esterification is a chemical reaction between an alcohol and a carboxylic acid, producing an ester and water.
Hydrocarbons are composed of: A) Hydrogen and nitrogen B) Carbon and oxygen C) Hydrogen and oxygen D) Hydrogen and carbon Answer: D Explanation: Hydrocarbons are organic compounds made entirely of hydrogen and carbon atoms.
Which of the following has a carboxyl group? A) CH₃COOH B) CH₃OH C) C₂H₆ D) CH₃CHO Answer: A Explanation: CH₃COOH (acetic acid) contains the –COOH group, a carboxyl group.
The boiling point of organic compounds increases with: A) Decreasing molar mass B) Increase in temperature C) Increase in carbon chain length D) More branching Answer: C Explanation: Longer carbon chains have more surface area and stronger van der Waals forces, leading to higher boiling points.
Which is not a functional group? A) –COOH B) –OH C) –CHO D) –CH₄ Answer: D Explanation: –CH₄ is not a functional group; it's a complete molecule (methane).
The functional group in aldehydes is: A) –COOH B) –CHO C) –OH D) –CO Answer: B Explanation: Aldehydes contain the –CHO group, where a carbon is double-bonded to oxygen and single-bonded to hydrogen.
Ethanol and methanol differ by: A) One oxygen B) One carbon and two hydrogen atoms C) One hydrogen only D) Nothing Answer: B Explanation: Methanol is CH₃OH and ethanol is C₂H₅OH; they differ by CH₂ group (one carbon and two hydrogens).
The molecular formula of methane is: A) CH₄ B) CH₃ C) C₂H₆ D) C₂H₂ Answer: A Explanation: Methane consists of one carbon atom and four hydrogen atoms (CH₄).
Natural gas mainly consists of: A) Ethane B) Propane C) Butane D) Methane Answer: D Explanation: Methane (CH₄) is the major component of natural gas.
The term 'alkyl' refers to: A) A group of acids B) Hydroxyl group C) A hydrocarbon group derived from alkane D) Halogen Answer: C Explanation: Alkyl groups are fragments of alkanes with one hydrogen removed (e.g., CH₃–, C₂H₅–).
Which process separates petroleum into useful products? A) Filtration B) Electrolysis C) Fractional distillation D) Decantation Answer: C Explanation: Fractional distillation separates petroleum based on boiling points of its components.
The polar group in alcohols increases: A) Solubility in water B) Boiling point C) Reactivity D) All of the above Answer: D Explanation: The polar –OH group in alcohols increases their ability to hydrogen bond, affecting all listed properties.

The functional group of alkyl halides is: A) –X (halogen) B) –OH C) –COOH D) –CHO Answer: A Explanation: Alkyl halides contain a halogen atom (X = Cl, Br, I, F) bonded to a carbon. Chapter 4: Biochemistry

Biochemistry is the study of: A) Non-living things B) Living organisms and chemical processes C) Minerals and ores D) Gases and their properties Answer: B Explanation: Biochemistry focuses on the chemical processes and substances that occur within living organisms.
Proteins are made up of: A) Fatty acids B) Glucose molecules C) Amino acids D) Nucleotides Answer: C Explanation: Proteins are polymers of amino acids linked by peptide bonds.
The building block of carbohydrates is: A) Amino acid B) Glucose C) Fatty acid D) Glycerol Answer: B Explanation: Glucose is the monomer unit of carbohydrates such as starch and cellulose.
Which of the following is a polysaccharide? A) Glucose B) Sucrose C) Starch D) Fructose Answer: C Explanation: Starch is a polysaccharide made up of many glucose units.
The simplest unit of a protein is: A) Nucleotide B) Monosaccharide C) Amino acid D) Lipid Answer: C Explanation: Amino acids are the monomeric units that combine to form proteins.
Lipids are composed of: A) Amino acids B) Nucleotides C) Fatty acids and glycerol D) Sugars Answer: C Explanation: Lipids such as fats are made by combining fatty acids with glycerol.
Enzymes are: A) Carbohydrates B) Lipids C) Proteins D) Fats Answer: C Explanation: Enzymes are biological catalysts made of proteins that speed up chemical reactions in cells.
Which of the following is a nucleic acid? A) DNA B) ATP C) Enzyme D) Glucose Answer: A Explanation: DNA (Deoxyribonucleic Acid) is a nucleic acid responsible for storing genetic information.
The main function of carbohydrates is: A) Growth B) Energy supply C) Cell division D) Hormone production Answer: B Explanation: Carbohydrates are the body’s primary source of energy.
Which is a disaccharide? A) Glucose B) Fructose C) Maltose D) Galactose Answer: C Explanation: Maltose is made from two glucose units and is a disaccharide.
Proteins contain which elements? A) C, H, O only B) C, H, O, N C) C, H, O, S D) C, H, O, N, S Answer: D Explanation: Proteins contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
Which vitamin is fat soluble? A) Vitamin B B) Vitamin C C) Vitamin A D) Vitamin B12 Answer: C Explanation: Vitamin A is fat-soluble, stored in body fat, unlike water-soluble vitamins like B and C.
Which of the following is not a component of nucleotide? A) Sugar B) Phosphate C) Nitrogen base D) Glycerol Answer: D Explanation: Nucleotides consist of a sugar, a phosphate group, and a nitrogenous base; glycerol is not part of them.
Which is the sugar in RNA? A) Deoxyribose B) Glucose C) Ribose D) Maltose Answer: C Explanation: RNA contains the sugar ribose, while DNA contains deoxyribose.
DNA is found mainly in: A) Cytoplasm B) Ribosome C) Nucleus D) Cell membrane Answer: C Explanation: In eukaryotic cells, DNA is primarily located in the nucleus.
An enzyme speeds up a reaction by: A) Increasing product B) Lowering activation energy C) Increasing temperature D) Increasing reactant Answer: B Explanation: Enzymes lower the activation energy needed for a chemical reaction to occur.
Which macromolecule stores genetic information? A) Lipids B) Proteins C) DNA D) Carbohydrates Answer: C Explanation: DNA stores the genetic blueprint for an organism.
Sucrose is made of: A) Glucose + glucose B) Glucose + fructose C) Glucose + galactose D) Fructose + galactose Answer: B Explanation: Sucrose is a disaccharide formed from one glucose and one fructose molecule.
Lipids are insoluble in: A) Alcohol B) Ether C) Water D) Chloroform Answer: C Explanation: Lipids are non-polar and do not dissolve in water, a polar solvent.
Peptide bond is found in: A) Lipids B) Nucleic acids C) Proteins D) Carbohydrates Answer: C Explanation: Peptide bonds link amino acids together in proteins.
Vitamin D is important for: A) Vision B) Blood clotting C) Calcium absorption D) Skin color Answer: C Explanation: Vitamin D helps the body absorb calcium, which is essential for healthy bones and teeth.
A protein may contain how many amino acids? A) 5–50 B) 60–6000 C) 1–20 D) 10000–20000 Answer: B Explanation: Proteins can range from dozens to thousands of amino acids, typically within 60–6000.
Which of the following is a water-soluble vitamin? A) Vitamin A B) Vitamin D C) Vitamin B D) Vitamin E Answer: C Explanation: Vitamin B complex (and Vitamin C) are water-soluble and not stored in the body.
Enzymes work best at a specific: A) Pressure B) Temperature and pH C) Volume D) Color Answer: B Explanation: Enzymes are highly sensitive to changes in temperature and pH, working best at optimum levels.
DNA contains: A) Ribose B) Uracil C) Deoxyribose D) Glycerol Answer: C Explanation: DNA includes the sugar deoxyribose, while RNA contains ribose.
Which macromolecule is not a polymer? A) Carbohydrate B) Lipid C) Protein D) Nucleic acid Answer: B Explanation: Lipids are not true polymers as they are not made from repeating monomer units in a chain.
A fatty acid with no double bonds is: A) Saturated B) Unsaturated C) Polyunsaturated D) Reactive Answer: A Explanation: Saturated fatty acids have only single bonds between carbon atoms.
RNA differs from DNA by containing: A) Ribose and uracil B) Deoxyribose and thymine C) Glycerol and uracil D) Glucose and cytosine Answer: A Explanation: RNA contains ribose sugar and the nitrogen base uracil instead of thymine.
Which of the following stores energy long-term? A) Glucose B) Lipids C) DNA D) Proteins Answer: B Explanation: Lipids are excellent for long-term energy storage due to their high caloric value.

The nitrogen base uracil is found only in: A) DNA B) Proteins C) RNA D) Carbohydrates Answer: C Explanation: Uracil replaces thymine in RNA and is not found in DNA. Chapter 5: Environmental Chemistry I – The Atmosphere

The atmosphere is the layer of gases surrounding: A) The sun B) The ocean C) The earth D) The moon Answer: C Explanation: The Earth is surrounded by a layer of gases called the atmosphere, which supports life by providing oxygen, trapping heat, and blocking harmful radiation.
The most abundant gas in the atmosphere is: A) Oxygen B) Nitrogen C) Carbon dioxide D) Argon Answer: B Explanation: Nitrogen makes up about 78% of Earth's atmosphere, making it the most abundant gas.
Which gas makes up about 21% of the atmosphere? A) Nitrogen B) Oxygen C) Carbon dioxide D) Argon Answer: B Explanation: Oxygen is the second most abundant gas in the atmosphere and is essential for respiration.
Which atmospheric layer contains the ozone layer? A) Troposphere B) Stratosphere C) Mesosphere D) Thermosphere Answer: B Explanation: The ozone layer is located in the stratosphere, where it absorbs harmful ultraviolet (UV) radiation from the sun.
Ozone is important because it: A) Causes acid rain B) Produces smog C) Blocks harmful UV rays D) Increases temperature Answer: C Explanation: Ozone in the stratosphere protects living organisms by filtering out harmful UV radiation.
Which gas is a greenhouse gas? A) Oxygen B) Nitrogen C) Carbon dioxide D) Neon Answer: C Explanation: Carbon dioxide (CO₂) traps heat in the atmosphere, contributing to the greenhouse effect and global warming.
The atmospheric layer closest to Earth is: A) Stratosphere B) Mesosphere C) Troposphere D) Thermosphere Answer: C Explanation: The troposphere is the lowest layer where weather occurs and where humans live.
The harmful effect of UV radiation is: A) Global warming B) Skin cancer C) Earthquake D) Acid rain Answer: B Explanation: Exposure to UV radiation can damage skin cells and lead to skin cancer.
Air pollution mainly affects the: A) Stratosphere B) Troposphere C) Mesosphere D) Thermosphere Answer: B Explanation: Most air pollution occurs in the troposphere due to human activities like burning fossil fuels.
Which of the following is a primary air pollutant? A) Ozone B) Sulphur dioxide C) Peroxyacetyl nitrate D) Smog Answer: B Explanation: Sulphur dioxide is directly emitted from sources like factories and vehicles, making it a primary pollutant.
Which of these is a secondary pollutant? A) SO₂ B) NO₂ C) Ozone D) CO Answer: C Explanation: Secondary pollutants like ozone form in the atmosphere through chemical reactions between primary pollutants and other atmospheric components.
Which one of the following is a natural source of air pollution? A) Factories B) Automobiles C) Forest fires D) Industrial waste Answer: C Explanation: Forest fires occur naturally and release smoke, ash, and gases that pollute the air.
The ozone molecule consists of: A) 2 oxygen atoms B) 3 oxygen atoms C) 1 oxygen atom D) 4 oxygen atoms Answer: B Explanation: Ozone (O₃) is a molecule made up of three oxygen atoms.
Smog is a mixture of smoke and: A) Dust B) Gas C) Fog D) Rain Answer: C Explanation: Smog forms from the combination of smoke and fog, especially in cities with heavy pollution.
Acid rain is caused by: A) O₂ and H₂O B) CO₂ and SO₂ C) SO₂ and NO₂ D) CO and NO Answer: C Explanation: Sulphur dioxide and nitrogen dioxide react with water in the atmosphere to form acids, which fall as acid rain.
Which pollutant reduces the oxygen-carrying capacity of blood? A) CO₂ B) O₃ C) CO D) SO₂ Answer: C Explanation: Carbon monoxide (CO) binds to hemoglobin more strongly than oxygen, reducing its ability to transport oxygen in the blood.
Which layer of the atmosphere has the highest concentration of ozone? A) Troposphere B) Stratosphere C) Thermosphere D) Exosphere Answer: B Explanation: The ozone layer, which absorbs UV radiation, is located in the stratosphere.
CFCs (Chlorofluorocarbons) destroy: A) Carbon dioxide B) Nitrogen C) Oxygen D) Ozone Answer: D Explanation: CFCs break down ozone molecules in the stratosphere, leading to ozone layer depletion.
Greenhouse effect causes: A) Cooling of Earth B) Global warming C) Acid rain D) Ozone layer recovery Answer: B Explanation: The greenhouse effect traps heat in Earth’s atmosphere, contributing to an increase in global temperatures.
Which pollutant is responsible for photochemical smog? A) SO₂ B) CO C) NO₂ D) O₃ Answer: C Explanation: Nitrogen dioxide (NO₂) reacts with sunlight and other pollutants to form photochemical smog.
Air pollutants that come directly from the source are called: A) Secondary pollutants B) Tertiary pollutants C) Primary pollutants D) Natural pollutants Answer: C Explanation: Primary pollutants are emitted directly into the atmosphere, such as CO, NO, and SO₂.
Ozone hole is mainly due to: A) Carbon dioxide B) Methane C) Chlorofluorocarbons (CFCs) D) Lead compounds Answer: C Explanation: CFCs release chlorine atoms in the stratosphere that break down ozone molecules.
Which layer is above the stratosphere? A) Troposphere B) Mesosphere C) Thermosphere D) Lithosphere Answer: B Explanation: The mesosphere lies above the stratosphere and is where meteors burn up.
Which gas contributes least to the greenhouse effect? A) CO₂ B) CH₄ C) N₂O D) O₂ Answer: D Explanation: Oxygen does not trap heat significantly and contributes least to the greenhouse effect.
The process by which plants absorb CO₂ and release O₂ is: A) Respiration B) Combustion C) Photosynthesis D) Fermentation Answer: C Explanation: In photosynthesis, plants convert carbon dioxide and water into glucose and oxygen using sunlight.
Which of these is not a greenhouse gas? A) Water vapor B) Methane C) Nitrogen D) Carbon dioxide Answer: C Explanation: Nitrogen makes up most of the atmosphere but does not trap heat like greenhouse gases.
Which human activity contributes most to air pollution? A) Agriculture B) Transportation C) Fishing D) Forestry Answer: B Explanation: Vehicles emit large quantities of pollutants such as CO, NOx, and hydrocarbons.
Nitrogen oxides in air are primarily produced from: A) Soil erosion B) Lightning C) Combustion engines D) Water pollution Answer: C Explanation: High-temperature combustion in engines leads to the formation of nitrogen oxides (NOx).
The protective function of ozone is to absorb: A) Infrared radiation B) X-rays C) Ultraviolet radiation D) Visible light Answer: C Explanation: Ozone absorbs harmful UV radiation, protecting living organisms from its effects.

Which gas causes depletion of the ozone layer? A) CO₂ B) NO₂ C) CFC D) CH₄ Answer: C Explanation: CFCs release chlorine atoms in the stratosphere, which catalytically destroy ozone molecules. Chapter 6: Environmental Chemistry II – Water

The chemical formula of water is: A) H₂O₂ B) H₂O C) HO₂ D) OH Answer: B Explanation: Water consists of two hydrogen atoms bonded to one oxygen atom, hence the formula H₂O.
Water is a universal: A) Base B) Solvent C) Acid D) Compound Answer: B Explanation: Water is called the universal solvent because it dissolves more substances than any other liquid.
Hard water contains: A) NaCl B) Ca²⁺ and Mg²⁺ ions C) CO₂ D) H₂O₂ Answer: B Explanation: Hard water contains dissolved calcium and magnesium ions, which interfere with soap lathering.
Temporary hardness of water is due to: A) CaSO₄ B) MgCl₂ C) Ca(HCO₃)₂ D) NaCl Answer: C Explanation: Temporary hardness is caused by bicarbonates of calcium and magnesium, which can be removed by boiling.
Permanent hardness of water is removed by: A) Boiling B) Adding lime C) Ion exchange method D) Filtration Answer: C Explanation: Permanent hardness caused by chlorides and sulfates of Ca²⁺ and Mg²⁺ can be removed by ion-exchange resins.
Soft water produces more: A) Acids B) Bases C) Lather with soap D) Carbon dioxide Answer: C Explanation: Soft water lacks calcium and magnesium ions and easily forms lather with soap.
The process of removing impurities from water is called: A) Fermentation B) Distillation C) Purification D) Neutralization Answer: C Explanation: Water purification involves removing physical, chemical, and biological contaminants.
Reverse osmosis is used for: A) Boiling water B) Freezing water C) Desalination D) Hardening water Answer: C Explanation: Reverse osmosis removes salts and other impurities from seawater, making it suitable for drinking.
The method to remove temporary hardness is: A) Filtration B) Boiling C) Adding detergent D) Oxidation Answer: B Explanation: Boiling precipitates bicarbonates, thereby removing temporary hardness.
Water pollution is mainly caused by: A) Trees B) Marine animals C) Industrial waste D) Clouds Answer: C Explanation: Industries discharge harmful chemicals into water bodies, causing pollution.
Which is a major cause of eutrophication? A) Acid rain B) Phosphate detergents C) Carbon dioxide D) Iron salts Answer: B Explanation: Phosphates from detergents promote excessive algae growth, leading to eutrophication.
Eutrophication leads to: A) Increased oxygen B) Death of aquatic life C) Better drinking water D) Decreased algae Answer: B Explanation: Overgrowth of algae reduces oxygen levels in water, killing aquatic organisms.
Detergents are a major cause of: A) Air pollution B) Soil pollution C) Water pollution D) Thermal pollution Answer: C Explanation: Detergents, especially non-biodegradable ones, pollute water bodies.
Heavy metals in water can cause: A) Good taste B) Cancer C) Color D) Bubbles Answer: B Explanation: Heavy metals like lead, mercury, and arsenic are toxic and carcinogenic.
Which method is used in water treatment plants? A) Electrolysis B) Sedimentation and filtration C) Distillation D) Chromatography Answer: B Explanation: Sedimentation and filtration remove suspended particles and sediments from water.
Chlorination of water is done to: A) Remove hardness B) Add minerals C) Kill bacteria D) Increase pH Answer: C Explanation: Chlorine is added to disinfect water and kill pathogenic microorganisms.
Water that is fit for drinking is called: A) Soft water B) Mineral water C) Distilled water D) Potable water Answer: D Explanation: Potable water is safe and suitable for human consumption.
The unit for measuring water hardness is: A) ppm B) Molarity C) kg/m³ D) mg/L Answer: A Explanation: Hardness is commonly measured in parts per million (ppm), indicating concentration of Ca²⁺/Mg²⁺ ions.
Excess fluoride in water causes: A) Skin rash B) Dental fluorosis C) Anemia D) Hair loss Answer: B Explanation: Fluoride above safe levels can discolor and damage teeth (dental fluorosis).
Safe level of fluoride in drinking water is: A) 5.0 ppm B) 2.5 ppm C) 1.0 ppm D) 0.01 ppm Answer: C Explanation: Fluoride levels around 1.0 ppm are considered safe and effective in preventing tooth decay.
Biodegradable pollutants are broken down by: A) Light B) Air C) Microorganisms D) Metals Answer: C Explanation: Biodegradable pollutants are decomposed naturally by bacteria and fungi.
Which of the following is non-biodegradable? A) Paper B) DDT C) Food waste D) Animal dung Answer: B Explanation: DDT is a synthetic pesticide that resists microbial degradation and persists in the environment.
Polluted water can cause: A) Typhoid B) Malaria C) Cancer D) All of the above Answer: D Explanation: Contaminated water is linked to a variety of diseases, including infectious and chronic conditions.
Which disease is spread through contaminated water? A) Tuberculosis B) Diabetes C) Cholera D) Arthritis Answer: C Explanation: Cholera is a bacterial disease transmitted through water contaminated with human waste.
Excess nitrate in water causes: A) Blue baby syndrome B) Jaundice C) Ulcers D) Hair fall Answer: A Explanation: High nitrate levels interfere with oxygen transport in infants, causing methemoglobinemia or "blue baby syndrome."
The process of water seeping into ground is called: A) Evaporation B) Percolation C) Condensation D) Sublimation Answer: B Explanation: Percolation is the movement of water through soil and porous materials into underground reservoirs.
Which of the following is not a method of water conservation? A) Rainwater harvesting B) Flood irrigation C) Fixing leakages D) Using low-flow fixtures Answer: B Explanation: Flood irrigation wastes water; it is not a conservation method.
Reverse osmosis membrane removes: A) Only salts B) All impurities C) Only viruses D) Only gases Answer: B Explanation: Reverse osmosis removes a wide range of impurities including salts, bacteria, and organic materials.
Which method involves use of activated carbon? A) Boiling B) Distillation C) Filtration D) Adsorption Answer: D Explanation: Activated carbon adsorbs impurities and is widely used in water purification systems.

Most of the freshwater on Earth is stored in: A) Rivers B) Lakes C) Glaciers and ice caps D) Oceans Answer: C Explanation: Around 69% of Earth’s freshwater is trapped in glaciers and ice caps. Chapter 7: Analytical Chemistry

Analytical chemistry deals with: A) Manufacturing of chemicals B) Studying weather C) Identification and quantification of substances D) Biological processes Answer: C Explanation: Analytical chemistry focuses on identifying what substances are present in a sample and in what amount.
The branch of chemistry that analyzes the composition of matter is called: A) Physical chemistry B) Organic chemistry C) Analytical chemistry D) Inorganic chemistry Answer: C Explanation: Analytical chemistry is the field that determines the chemical composition of materials.
Which technique is used to separate colored substances? A) Filtration B) Chromatography C) Distillation D) Sedimentation Answer: B Explanation: Chromatography separates components of a mixture based on their different affinities for a stationary and a mobile phase.
The stationary phase in chromatography is usually: A) Water B) Alcohol C) Paper D) Air Answer: C Explanation: In paper chromatography, paper serves as the stationary phase.
Rf value in chromatography is calculated by: A) Solvent front / distance travelled by solute B) Distance travelled by solute / solvent front C) Distance from origin to base D) Color intensity / solvent Answer: B Explanation: Rf = (distance moved by substance) / (distance moved by solvent front).
Spectroscopy involves the interaction of matter with: A) Heat B) Radiation C) Pressure D) Magnetism Answer: B Explanation: Spectroscopy studies how matter interacts with various forms of electromagnetic radiation.
The branch that measures conductivity of solutions is called: A) Conductometry B) Spectroscopy C) Chromatography D) Calorimetry Answer: A Explanation: Conductometry involves measuring the electrical conductivity of a solution to analyze ionic concentration.
Which method is used to detect the presence of metal ions? A) Conductometry B) Chromatography C) Flame test D) Adsorption Answer: C Explanation: Flame tests identify metal ions based on the color they emit when heated.
The process of measuring amount of substance present is: A) Qualitative analysis B) Quantitative analysis C) Flame test D) Filtration Answer: B Explanation: Quantitative analysis determines how much of a substance is present in a sample.
The method used to find unknown concentration using known concentration is: A) Titration B) Filtration C) Adsorption D) Combustion Answer: A Explanation: Titration uses a solution of known concentration to determine the concentration of another substance.
In chromatography, the mobile phase is: A) Paper B) Ink C) Solvent D) Pigment Answer: C Explanation: The mobile phase is the solvent that moves through the stationary phase and carries the components with it.
Which is not used in titration? A) Burette B) Pipette C) Thermometer D) Indicator Answer: C Explanation: A thermometer is not part of standard titration apparatus; titration uses burette, pipette, and indicators.
The endpoint in titration is shown by: A) Bubbles B) Temperature rise C) Color change D) Smoke Answer: C Explanation: A visible color change marks the endpoint of a titration, indicating reaction completion.
The part of spectroscopy that uses visible light is: A) Infrared spectroscopy B) Ultraviolet spectroscopy C) Visible spectroscopy D) Mass spectroscopy Answer: C Explanation: Visible spectroscopy uses light in the visible range to analyze substances.
Which instrument measures light absorbance? A) Thermometer B) Colorimeter C) Conductometer D) Galvanometer Answer: B Explanation: A colorimeter measures how much light is absorbed by a colored solution.
Which is a qualitative method of analysis? A) Titration B) Gravimetric analysis C) Flame test D) Spectrophotometry Answer: C Explanation: The flame test provides qualitative information about the presence of certain metal ions.
Which method separates substances based on polarity? A) Titration B) Conductometry C) Chromatography D) Spectroscopy Answer: C Explanation: Chromatography separates components based on differences in polarity and solubility.
In chromatography, a higher Rf value indicates: A) Slower moving substance B) Faster moving substance C) Substance not detected D) No result Answer: B Explanation: A higher Rf value means the substance traveled farther with the solvent, indicating lower affinity for the stationary phase.
Which ion gives a brick red flame? A) Na⁺ B) K⁺ C) Ca²⁺ D) Cu²⁺ Answer: C Explanation: Calcium ions give a characteristic brick red color in a flame test.
Which metal ion gives a green flame? A) Calcium B) Barium C) Potassium D) Sodium Answer: B Explanation: Barium ions give a green flame during the flame test.
Titration between acid and base is called: A) Neutralization titration B) Redox titration C) Complexometric titration D) Precipitation titration Answer: A Explanation: Neutralization titration involves the reaction between an acid and a base to determine concentration.
Indicator used in acid-base titration is: A) Potassium dichromate B) Phenolphthalein C) Iodine D) Water Answer: B Explanation: Phenolphthalein is a common acid-base indicator that changes color near neutral pH.
In conductometry, conductivity is measured in: A) Siemens (S) B) Volts (V) C) Ohms (Ω) D) Amperes (A) Answer: A Explanation: Electrical conductivity is measured in Siemens, indicating how well a solution conducts electricity.
Which part of titration apparatus holds the standard solution? A) Pipette B) Burette C) Flask D) Beaker Answer: B Explanation: The burette contains the standard solution, which is added dropwise during titration.
Which instrument is used in spectroscopic analysis? A) Spectrophotometer B) Microscope C) Barometer D) Oscilloscope Answer: A Explanation: A spectrophotometer measures the amount of light absorbed by a solution.
Gravimetric analysis involves measurement of: A) Color B) Mass C) Volume D) Temperature Answer: B Explanation: Gravimetric analysis quantifies substances based on the mass of a solid formed during a reaction.
Which ion gives a golden yellow flame? A) Potassium B) Sodium C) Copper D) Barium Answer: B Explanation: Sodium gives a bright golden yellow flame, which is easily visible and distinct.
Which separation technique is best for color mixtures? A) Filtration B) Evaporation C) Chromatography D) Decantation Answer: C Explanation: Chromatography is ideal for separating and analyzing colored mixtures like inks and dyes.
The term 'analyte' refers to: A) Solvent used B) Known substance C) Substance being analyzed D) Titration apparatus Answer: C Explanation: The analyte is the substance whose presence or concentration is being determined.

The purpose of indicator in titration is to: A) Measure volume B) Maintain temperature C) Show completion of reaction D) Prevent mixing Answer: C Explanation: Indicators signal the end point of a titration through a visible color change. Chapter 8: Industrial Chemistry

Industrial chemistry deals with: A) Atoms and elements B) Laboratory reactions C) Large-scale chemical production D) Natural resources only Answer: C Explanation: Industrial chemistry focuses on chemical processes and reactions used in large-scale manufacturing of useful products.
The raw materials for soap production are: A) Acid and water B) Oil and base C) Sugar and water D) Salt and alcohol Answer: B Explanation: Soaps are made by reacting oils or fats with a strong base like NaOH or KOH in a process called saponification.
Saponification is the process of making: A) Glass B) Fertilizer C) Soap D) Plastic Answer: C Explanation: Saponification is the reaction of fats or oils with an alkali to produce soap and glycerol.
Main ingredients of soap are: A) Sulfur and acid B) Fatty acids and alkali C) Water and sugar D) Proteins and oils Answer: B Explanation: Soaps are sodium or potassium salts of fatty acids, made from fat and a strong alkali.
Hard water reduces the effectiveness of: A) Acids B) Soaps C) Detergents D) Bases Answer: B Explanation: In hard water, soap reacts with calcium and magnesium ions to form scum, reducing its cleaning ability.
Which of the following is a synthetic detergent? A) Sodium stearate B) Sodium lauryl sulfate C) Potassium hydroxide D) Acetic acid Answer: B Explanation: Sodium lauryl sulfate is a synthetic detergent that performs well even in hard water.
In the Haber process, ammonia is prepared using: A) H₂ and O₂ B) H₂ and N₂ C) CO₂ and H₂ D) N₂ and O₂ Answer: B Explanation: The Haber process combines hydrogen and nitrogen gases to synthesize ammonia (NH₃).
The catalyst used in Haber process is: A) Nickel B) Iron C) Copper D) Platinum Answer: B Explanation: Finely divided iron acts as a catalyst in the Haber process to increase the reaction rate.
Temperature used in Haber process is approximately: A) 100°C B) 200°C C) 450°C D) 700°C Answer: C Explanation: The optimal temperature for the Haber process is about 450°C to achieve a balance between rate and yield.
Pressure used in ammonia production is about: A) 1 atm B) 5 atm C) 200 atm D) 500 atm Answer: C Explanation: A high pressure of around 200 atmospheres is used to favor ammonia formation.
Main use of ammonia is in: A) Plastics B) Food industry C) Fertilizers D) Paints Answer: C Explanation: Ammonia is primarily used in the production of fertilizers like urea and ammonium nitrate.
Nitrogen is obtained from: A) Rocks B) Soil C) Air D) Sea water Answer: C Explanation: Nitrogen is extracted from atmospheric air using fractional distillation of liquid air.
The source of hydrogen for Haber process is: A) Electrolysis of water B) Photosynthesis C) Fermentation D) Decomposition Answer: A Explanation: Hydrogen is commonly produced by electrolysis of water or steam reforming of methane.
The chemical used to soften water is: A) NaCl B) Na₂CO₃ C) HCl D) CaSO₄ Answer: B Explanation: Sodium carbonate (Na₂CO₃), also known as washing soda, removes Ca²⁺ and Mg²⁺ ions from hard water.
Which of the following is biodegradable? A) Detergent B) Soap C) Plastic D) Glass Answer: B Explanation: Soaps are biodegradable as they are made from natural fatty acids that break down easily.
Soaps are made by reacting fat with: A) HCl B) NaOH or KOH C) NH₄OH D) H₂O Answer: B Explanation: Soap is produced when fats react with sodium or potassium hydroxide in the saponification process.
The process of breaking down fats into soap is called: A) Polymerization B) Esterification C) Saponification D) Neutralization Answer: C Explanation: Saponification is the hydrolysis of fats or oils in the presence of a base to form soap and glycerol.
Main disadvantage of soap in hard water is: A) More foam B) Poor lather C) High solubility D) No reaction Answer: B Explanation: Soap forms insoluble salts with Ca²⁺ and Mg²⁺ in hard water, preventing lather formation.
Detergents work well in: A) Distilled water only B) Acidic water C) Hard and soft water D) Rainwater only Answer: C Explanation: Synthetic detergents remain effective in both hard and soft water because they do not form scum.
Detergents are made from: A) Animal fats B) Synthetic chemicals C) Plants only D) Sea water Answer: B Explanation: Detergents are produced from petrochemicals and synthetic compounds rather than natural fats.
Which compound is formed in the reaction between fat and sodium hydroxide? A) Glycerol B) Glucose C) Ethanol D) Starch Answer: A Explanation: The saponification reaction produces soap and glycerol as a by-product.
The by-product of soap making is: A) Water B) Glycerol C) Salt D) Ammonia Answer: B Explanation: Glycerol (glycerin) is a valuable by-product used in cosmetics and pharmaceuticals.
The use of detergents instead of soap increases: A) Water pollution B) Biodegradation C) Foam quality D) Natural resource use Answer: A Explanation: Detergents are often non-biodegradable and contribute to water pollution.
Soap molecules have: A) Hydrophobic and hydrophilic ends B) Only hydrophilic ends C) Only hydrophobic ends D) No polarity Answer: A Explanation: One end of a soap molecule is hydrophobic (repels water) and the other is hydrophilic (attracts water), aiding in cleansing.
The cleansing action of soap is due to: A) High pH B) Presence of oil C) Micelle formation D) Low temperature Answer: C Explanation: Soap molecules form micelles that trap oil and grease, allowing them to be washed away with water.
In industry, which method is used to produce hydrogen? A) Cracking B) Steam reforming of methane C) Fermentation D) Electrolysis Answer: B Explanation: Steam reforming of methane is the most common industrial method for hydrogen production.
Ammonia is a gas at: A) 100°C B) Room temperature C) 0°C D) 200°C Answer: B Explanation: Ammonia is a colorless gas with a pungent odor at room temperature.
Which of the following is not an industrial chemical? A) Soap B) Glycerol C) Vitamin C D) Detergent Answer: C Explanation: While Vitamin C is important in nutrition, it is not classified as an industrial chemical.
Which is more effective in hard water? A) Soap B) Detergent C) Vinegar D) Salt Answer: B Explanation: Detergents clean effectively in hard water without forming scum, unlike soap.
Which industrial process is used to make fertilizers? A) Solvay process B) Contact process C) Haber process D) Ostwald process Answer: C Explanation: The Haber process produces ammonia, which is a key ingredient in nitrogen-based fertilizers.

Physics

Chapter 1: General Wave Properties

A wave is best described as: A) Matter transfer B) Vibration of air only C) Energy transfer through a medium D) Energy transfer through solid only Answer: C Explanation: A wave transfers energy from one point to another through a medium without transferring matter.

Which of the following is a mechanical wave? A) Radio wave B) Sound wave C) Infrared ray D) Gamma ray Answer: B Explanation: Sound is a mechanical wave that requires a medium (solid, liquid, or gas) to travel.

Transverse waves have particles moving: A) In circles B) Along the wave direction C) Perpendicular to wave direction D) Randomly Answer: C Explanation: In transverse waves, particles oscillate at right angles to the direction of wave propagation.

Longitudinal waves exhibit: A) Crests and troughs B) Compressions and rarefactions C) Reflection only D) No motion Answer: B Explanation: Longitudinal waves compress and expand the medium in the same direction as the wave.

SI unit of frequency is: A) m/s B) N C) Hz D) J Answer: C Explanation: Hertz (Hz) is the standard unit for frequency, representing cycles per second.

The distance between two adjacent crests is called: A) Period B) Amplitude C) Frequency D) Wavelength Answer: D Explanation: Wavelength is the length between two consecutive crests or troughs in a wave.

The time required to complete one vibration is called: A) Period B) Amplitude C) Frequency D) Speed Answer: A Explanation: Period is the time taken for one complete wave cycle or vibration.

Wave speed formula is: A) v = fλ B) v = f + λ C) v = f − λ D) v = λ/f Answer: A Explanation: Wave speed (v) is calculated using the product of frequency (f) and wavelength (λ).

Amplitude refers to: A) Total wavelength B) Height from rest to crest C) Distance between two compressions D) Vibration count Answer: B Explanation: Amplitude is the maximum displacement from the rest position — linked to wave energy.

Which wave type needs a medium? A) X-rays B) Light C) Radio D) Sound Answer: D Explanation: Sound waves are mechanical and need a medium to propagate.

Which of these is an example of a transverse wave? A) Sound in air B) Light wave C) Seismic P-waves D) Sound in water Answer: B Explanation: Light is an electromagnetic transverse wave, traveling even in vacuum.

Longitudinal waves move particles: A) In circular motion B) At right angles to wave direction C) Back and forth in wave direction D) In a helical path Answer: C Explanation: Particles in longitudinal waves vibrate parallel to the wave’s direction.

In a slinky spring, waves can be: A) Longitudinal only B) Transverse only C) Neither D) Both types Answer: D Explanation: A slinky can demonstrate both longitudinal and transverse wave motions.

Which wave can travel through vacuum? A) Sound B) Water wave C) Light D) Earthquake wave Answer: C Explanation: Light is an electromagnetic wave and does not need a medium.

Wavelength is usually measured in: A) Seconds B) Meters C) Hertz D) Joules Answer: B Explanation: Wavelength is a measure of distance, typically in meters.

Energy in a wave moves from: A) End to start B) Particle to particle C) Only in solids D) With the medium Answer: B Explanation: Wave energy is passed through the medium as particles oscillate and transfer energy.

Transverse waves do NOT occur in: A) Solids B) Liquids C) Vacuum D) Air Answer: D Explanation: Air primarily supports longitudinal waves, not transverse ones.

One complete wave cycle includes: A) One crest only B) One crest and one trough C) Two crests D) Four compressions Answer: B Explanation: A full cycle consists of a crest and a trough (or compression and rarefaction).

What is produced when a stone is dropped in water? A) Light wave B) Longitudinal wave C) Sound wave D) Transverse wave Answer: D Explanation: Water ripples are transverse waves — the disturbance is up/down while the wave moves outward.

High frequency means: A) Long wavelength B) Short period C) Low speed D) Low amplitude Answer: B Explanation: High frequency corresponds to more cycles per second and hence a shorter period.

The number of vibrations per second is called: A) Wavelength B) Period C) Frequency D) Velocity Answer: C Explanation: Frequency is defined as the number of vibrations or cycles per second.

SI unit of wavelength is: A) Meter B) Second C) Hertz D) Newton Answer: A Explanation: Wavelength is a distance measure, so the SI unit is meters.

Which wave property changes with temperature in air? A) Frequency B) Wavelength C) Speed D) Amplitude Answer: C Explanation: The speed of sound in air varies with temperature — higher temperature increases speed.

Crests and troughs are associated with: A) Sound waves B) Longitudinal waves C) Transverse waves D) Electrons Answer: C Explanation: Crests and troughs are features of transverse waves.

Sound waves are: A) Transverse waves B) Longitudinal waves C) Electromagnetic D) Virtual waves Answer: B Explanation: Sound waves are longitudinal waves that travel as compressions and rarefactions.
The height of a wave from rest position is its: A) Frequency B) Amplitude C) Period D) Speed Answer: B Explanation: Amplitude is the wave’s maximum displacement from its rest position.

Mechanical waves transfer energy through: A) Space only B) Medium C) Vacuum D) None Answer: B Explanation: Mechanical waves require a medium for energy transfer (e.g., sound needs air).

Unit of wave speed is: A) Hz B) m/s C) N D) s/m Answer: B Explanation: Wave speed is measured in meters per second.

The source of wave energy is: A) Friction B) Motion C) Vibration D) Compression Answer: C Explanation: Vibration of particles is what generates wave motion and energy.

Which wave is both mechanical and longitudinal? A) Light B) Gamma rays C) Sound D) X-rays Answer: C Explanation: Sound is a mechanical and longitudinal wave that requires a medium to travel. Great! Continuing now with:

Chapter 2: Sound

Sound is produced due to: A) Motion B) Heat C) Vibration D) Light Answer: C Explanation: Sound originates from the vibration of objects, which create compressions and rarefactions in the surrounding medium.

Sound waves are: A) Transverse B) Longitudinal C) Electromagnetic D) Static Answer: B Explanation: In sound waves, particles of the medium vibrate parallel to the direction of wave propagation — a property of longitudinal waves.

Medium required for sound to travel: A) Not required B) Required C) Only vacuum D) Only gases Answer: B Explanation: Sound is a mechanical wave and needs a medium like air, water, or solid to travel.

Speed of sound is greatest in: A) Vacuum B) Water C) Steel D) Air Answer: C Explanation: Sound travels fastest in solids due to closely packed particles; thus, steel transmits sound more quickly than air or water.

Unit of frequency is: A) m B) s C) Hz D) N Answer: C Explanation: Frequency, which measures vibrations per second, is expressed in hertz (Hz).

Range of audible sound for humans: A) 0–10 Hz B) 20–20,000 Hz C) 1,000–10,000 Hz D) 30–30,000 Hz Answer: B Explanation: The human ear can typically detect sounds between 20 Hz and 20,000 Hz.

Sound below 20 Hz is called: A) Audible B) Ultrasonic C) Supersonic D) Infrasonic Answer: D Explanation: Infrasonic waves are those with frequencies below 20 Hz — too low to be heard by humans.

The speed of sound in air at room temperature is approximately: A) 330 m/s B) 3,000 m/s C) 150 m/s D) 100 m/s Answer: A Explanation: At 20°C, sound travels through air at about 330 m/s.

Echo is heard when reflected sound reaches the ear after: A) 0.01 s B) 0.05 s C) 0.1 s D) 0.2 s Answer: C Explanation: The human ear distinguishes two sounds if they are heard at least 0.1 seconds apart.

The device used to measure sound frequency is called: A) Thermometer B) Oscilloscope C) Tuning fork D) Frequency meter Answer: D Explanation: A frequency meter is specifically designed to measure the frequency of waves including sound.

A reflected sound is called: A) Refraction B) Echo C) Reverberation D) Tone Answer: B Explanation: An echo is the reflection of a sound wave from a surface back to the listener.

Ultrasonic waves have frequencies: A) Less than 20 Hz B) Between 20–20,000 Hz C) Greater than 20,000 Hz D) Equal to 1 Hz Answer: C Explanation: Frequencies above 20,000 Hz are classified as ultrasonic and are not audible to humans.

The loudness of sound depends on: A) Wavelength B) Frequency C) Amplitude D) Speed Answer: C Explanation: Greater amplitude results in louder sounds; amplitude measures energy in a sound wave.

Pitch of a sound is determined by its: A) Wavelength B) Frequency C) Amplitude D) Speed Answer: B Explanation: Pitch is how high or low a sound is; higher frequency means higher pitch.

Sound waves cannot travel through: A) Gases B) Solids C) Vacuum D) Liquids Answer: C Explanation: Sound requires a medium to travel; it cannot propagate through vacuum.

Musical sound has: A) Irregular waveform B) Random frequency C) Regular wave pattern D) No wavelength Answer: C Explanation: Musical sounds are periodic and have a regular waveform, unlike noise.

Noise is a: A) Regular sound B) Musical sound C) Disturbance in air D) Random and irregular sound Answer: D Explanation: Noise is irregular, disorganized sound with no regular pattern.

What changes when sound travels from air to water? A) Frequency B) Wavelength C) Loudness D) Pitch Answer: B Explanation: Frequency remains constant, but the speed and wavelength of sound change in different media.

SONAR uses: A) Radio waves B) Light waves C) Ultrasonic waves D) Infrared waves Answer: C Explanation: SONAR (Sound Navigation and Ranging) uses ultrasonic waves to detect underwater objects.

When sound is reflected repeatedly within a closed surface, it is called: A) Echo B) Reverberation C) Dispersion D) Reflection Answer: B Explanation: Reverberation is the persistence of sound due to multiple reflections.

Sound waves cannot be: A) Refracted B) Reflected C) Polarized D) Diffracted Answer: C Explanation: Only transverse waves can be polarized; sound, being longitudinal, cannot.

The speed of sound in water is about: A) 330 m/s B) 1,480 m/s C) 500 m/s D) 3,000 m/s Answer: B Explanation: Sound travels faster in water (~1,480 m/s) than in air due to higher particle density.

A sound of frequency 50 Hz has: A) Low pitch B) High pitch C) Infrasonic frequency D) Supersonic speed Answer: A Explanation: A 50 Hz sound has low frequency and hence a low pitch.

The quality or timbre of a sound is affected by: A) Amplitude B) Frequency C) Waveform D) Velocity Answer: C Explanation: The waveform or harmonic content gives sound its distinctive quality (e.g., same note on piano vs. violin).

Sound produced in the vocal cords travels through: A) Blood B) Vacuum C) Air D) Light Answer: C Explanation: Air acts as the medium through which sound travels from vocal cords to the listener.

Two sounds of same pitch and loudness but different sources are distinguished by: A) Echo B) Wavelength C) Timbre D) Reverberation Answer: C Explanation: Timbre allows us to distinguish between sounds of same frequency and amplitude.

When frequency increases, wavelength: A) Increases B) Decreases C) Becomes zero D) Remains same Answer: B Explanation: Wavelength and frequency are inversely related (v = fλ), so if one goes up, the other goes down.

Unit of sound level (loudness) is: A) Newton B) Decibel C) Pascal D) Hertz Answer: B Explanation: Loudness or intensity level of sound is measured in decibels (dB).

Which human organ detects sound? A) Nose B) Brain C) Ear D) Skin Answer: C Explanation: The ear is the sensory organ responsible for detecting and interpreting sound waves.
When sound hits a surface and returns, it is: A) Absorbed B) Reflected C) Diffracted D) Refracted Answer: B Explanation: Sound can bounce off surfaces and return, which is the process of reflection. Continuing with:

Chapter 3: Geometrical Optics

The bending of light when it passes from one medium to another is called: A) Reflection B) Dispersion C) Refraction D) Diffraction Answer: C Explanation: Refraction occurs when light changes speed and direction upon entering a medium with a different optical density.

The bouncing back of light from a surface is known as: A) Refraction B) Diffusion C) Reflection D) Polarization Answer: C Explanation: When light hits a reflective surface, such as a mirror, and bounces back, it is reflection.

In a plane mirror, the image formed is: A) Real and inverted B) Virtual and inverted C) Real and upright D) Virtual and upright Answer: D Explanation: A plane mirror always produces a virtual, erect, and laterally inverted image.

The angle between the incident ray and the normal is called: A) Refracted angle B) Angle of incidence C) Angle of deviation D) Angle of emergence Answer: B Explanation: The angle between the incoming ray and the normal line to the surface is the angle of incidence.

The laws of reflection state that: A) Angle of incidence equals angle of refraction B) Incident ray lies along the surface C) Angle of incidence equals angle of reflection D) Reflection is only in convex mirrors Answer: C Explanation: According to the law of reflection, the angle of incidence is always equal to the angle of reflection.

The image formed by a convex mirror is always: A) Real and inverted B) Virtual and erect C) Enlarged and real D) Diminished and inverted Answer: B Explanation: Convex mirrors always form virtual, erect, and diminished images regardless of the object's position.

Which mirror is used as a rear-view mirror in vehicles? A) Plane mirror B) Concave mirror C) Convex mirror D) None of these Answer: C Explanation: Convex mirrors give a wider field of view and always form erect images, making them ideal for vehicle mirrors.

The center of curvature lies in front of the mirror in a: A) Plane mirror B) Convex mirror C) Concave mirror D) None of these Answer: C Explanation: For concave mirrors, the center of curvature is on the same side as the object (front of the mirror).

The principal focus of a convex mirror is: A) Real B) Virtual C) Inverted D) Behind the mirror Answer: B Explanation: Convex mirrors have a virtual focus behind the mirror, where the reflected rays appear to diverge from.

If a light ray passes from air into glass, it: A) Bends away from normal B) Continues straight C) Bends towards normal D) Becomes faster Answer: C Explanation: Light slows down in denser media like glass and bends toward the normal.

The unit of refractive index is: A) m/s B) m C) Unitless D) Hz Answer: C Explanation: Refractive index is the ratio of speeds and hence has no unit.

A real image is always: A) Erect B) Virtual C) Inverted D) Smaller than object Answer: C Explanation: Real images are always inverted and can be projected on a screen.

Concave mirrors can form: A) Only virtual images B) Only real images C) Both real and virtual images D) No image Answer: C Explanation: Depending on the object’s position, a concave mirror can form both real and virtual images.

Light travels fastest in: A) Glass B) Air C) Water D) Diamond Answer: B Explanation: Light travels fastest in air and slowest in denser materials like diamond.

The focal length of a plane mirror is: A) Zero B) Infinite C) Negative D) Positive Answer: B Explanation: A plane mirror has an infinite focal length as it does not converge or diverge rays.

When light passes from glass to air, it: A) Speeds up and bends away from normal B) Slows down and bends towards normal C) Stops D) Travels undeviated Answer: A Explanation: Moving to a rarer medium like air increases speed and bends the ray away from the normal.

Lateral inversion is shown by: A) Convex mirror B) Plane mirror C) Concave mirror D) None of these Answer: B Explanation: Plane mirrors reverse left and right in the image — known as lateral inversion.

The principal axis of a mirror is: A) Curved path through the mirror B) The axis perpendicular to focus C) The line joining pole and center of curvature D) None of the above Answer: C Explanation: The principal axis is the straight line through the mirror’s pole and center of curvature.

In a mirror, the point from which all rays parallel to the principal axis appear to diverge is: A) Focus B) Center C) Pole D) Vertex Answer: A Explanation: This point is the principal focus of the mirror.

Refractive index of air is approximately: A) 0 B) 1 C) 1.5 D) 2 Answer: B Explanation: Air’s refractive index is about 1.0003, often approximated to 1.

A concave mirror gives an erect image when object is placed: A) Beyond center of curvature B) Between pole and focus C) At focus D) At center of curvature Answer: B Explanation: Within the focal length, concave mirrors produce virtual, erect, and magnified images.

The image formed by plane mirror is of the same: A) Size and orientation B) Size but inverted C) Size and real D) Orientation but smaller Answer: A Explanation: Plane mirrors produce images of the same size and upright orientation.

Refraction occurs because light: A) Changes direction due to reflection B) Changes medium and speed C) Changes frequency D) Increases amplitude Answer: B Explanation: Refraction is due to the change in speed of light when moving between different media.

Speed of light in vacuum is: A) 3 × 10⁶ m/s B) 3 × 10⁸ m/s C) 3 × 10⁴ m/s D) 3 × 10⁹ m/s Answer: B Explanation: The speed of light in vacuum is 3 × 10⁸ m/s — a fundamental constant.

Convex mirrors are used in: A) Shaving mirrors B) Vehicle headlights C) Rear-view mirrors D) Solar heaters Answer: C Explanation: Convex mirrors provide a wider field of view, ideal for rear-view purposes.

The image that can be captured on a screen is called: A) Virtual B) Real C) Imaginary D) Erect Answer: B Explanation: Real images can be projected on a screen, unlike virtual ones.

A convex mirror always forms: A) Inverted image B) Erect image C) Real image D) Enlarged image Answer: B Explanation: Convex mirrors always form erect, diminished, and virtual images.

Focal length is half of: A) Aperture B) Radius of curvature C) Wavelength D) Image height Answer: B Explanation: f = R/2, where R is the radius of curvature.

Light deviates more when the angle of incidence is: A) 0° B) Low C) High D) 90° Answer: C Explanation: Higher angle of incidence causes greater bending or deviation during refraction.

The image formed by concave mirror for a distant object is: A) Virtual and erect B) Real and inverted C) Virtual and inverted D) Real and erect Answer: B Explanation: Distant objects form real, inverted, and diminished images near the focus of a concave mirror. Continuing with:

Chapter 4: Turning Effect of Forces

Turning effect of a force is called: A) Work B) Energy C) Moment of force D) Power Answer: C Explanation: The tendency of a force to rotate an object about an axis is called the moment of force or torque.

The formula for moment of force is: A) Force × area B) Force × distance C) Force / distance D) Force × time Answer: B Explanation: Moment = Force × Perpendicular distance from pivot (M = F × d).

SI unit of moment is: A) Nm B) N/m C) Nm² D) N/s Answer: A Explanation: Since moment is force multiplied by distance, its SI unit is newton-meter (Nm).

A longer spanner makes it easier to loosen a nut because: A) More mass B) Less friction C) Greater moment D) Smaller distance Answer: C Explanation: A longer handle increases the perpendicular distance, increasing the moment and making turning easier.

A force produces no turning effect when it acts: A) At 90° to lever arm B) At pivot point C) Far from pivot D) Vertically Answer: B Explanation: If force is applied at the pivot, the perpendicular distance is zero, so moment is zero.

Moment of force is maximum when angle is: A) 0° B) 90° C) 45° D) 180° Answer: B Explanation: Torque is maximum when force is applied at right angles to the lever arm.

Clockwise moment is usually considered: A) Positive B) Negative C) Zero D) Always equal Answer: B Explanation: By convention, clockwise moments are taken as negative in calculations.

A seesaw is an example of: A) Pulley B) Gear C) Lever D) Inclined plane Answer: C Explanation: A seesaw is a type of lever, with the pivot at the center.

The point about which a body rotates is called: A) Axis B) Pivot C) Mass center D) Plane Answer: B Explanation: The pivot is the fixed point about which a lever rotates.

When clockwise and anticlockwise moments are equal, the system is in: A) Linear motion B) Rotational motion C) Equilibrium D) Acceleration Answer: C Explanation: Equal opposing moments balance each other, resulting in rotational equilibrium.

Principle of moments states: A) Total force is zero B) Total moments are equal C) Sum of clockwise moments = sum of anticlockwise moments D) Torque is zero Answer: C Explanation: For a body in equilibrium, total clockwise moments equal total anticlockwise moments.

Increasing the perpendicular distance of force: A) Decreases moment B) Increases moment C) No effect D) Changes direction Answer: B Explanation: Moment is directly proportional to the distance from the pivot (M = F × d).

The moment of a couple is calculated by: A) One force × one distance B) Either force × distance between forces C) Average force × distance D) Total force × distance Answer: B Explanation: Moment of couple = One force × perpendicular distance between the forces.

A couple produces: A) Translation B) Rotation C) Acceleration D) No motion Answer: B Explanation: A couple produces rotational motion without causing translation.

Two equal and opposite parallel forces form a: A) Lever B) Pulley C) Couple D) Balanced force Answer: C Explanation: A couple consists of two equal, opposite, and parallel forces acting at different points.

Which quantity is a vector? A) Moment of force B) Distance C) Mass D) Speed Answer: A Explanation: Moment (torque) has both magnitude and direction, so it is a vector quantity.

Which one is NOT a lever? A) Spoon B) Scissors C) Door D) Spring Answer: D Explanation: A spring is not a lever; it does not rotate about a pivot point.

First-class lever has: A) Load between fulcrum and effort B) Fulcrum between load and effort C) Effort between load and fulcrum D) No fixed pattern Answer: B Explanation: In a first-class lever (e.g., seesaw), the fulcrum is between load and effort.

Wheelbarrow is an example of: A) First-class lever B) Second-class lever C) Third-class lever D) Pulley Answer: B Explanation: In a wheelbarrow (2nd-class), the load is between the effort and fulcrum.

Human arm acts as: A) First-class lever B) Second-class lever C) Third-class lever D) No lever Answer: C Explanation: In the human arm, the effort is between the load and fulcrum — a third-class lever.

SI unit of torque is same as: A) Energy B) Force C) Work D) Moment Answer: D Explanation: Torque and moment are equivalent terms; both are measured in newton-meters.

Greater the torque: A) Smaller the turning effect B) Larger the turning effect C) No effect D) Stops rotation Answer: B Explanation: Torque directly determines the intensity of the turning effect.

One example of a couple is: A) Pushing a door B) Turning a steering wheel C) Pulling a rope D) Lifting a weight Answer: B Explanation: When you apply two opposite forces on a steering wheel, a couple is formed, causing rotation.

When a force is applied at a distance from the pivot, it creates: A) Torque B) Pressure C) Work D) Power Answer: A Explanation: Applying a force away from the pivot results in a torque.

Balanced seesaw shows: A) Zero force B) Zero torque C) Equal clockwise and anticlockwise moments D) Only motion Answer: C Explanation: A balanced seesaw demonstrates the principle of moments in equilibrium.

Which tool is designed to create torque? A) Ruler B) Hammer C) Wrench D) Screwdriver Answer: C Explanation: A wrench applies force at a distance to create torque for loosening or tightening.

The perpendicular distance in moment calculation is measured from: A) Load to pivot B) Line of action of force to pivot C) Axis to surface D) Edge of object Answer: B Explanation: Moment is calculated using the perpendicular distance from the pivot to the line of force.

A small force at a large distance can produce: A) No rotation B) Small moment C) Large moment D) Equilibrium only Answer: C Explanation: Moment increases with distance; even a small force can cause a strong turning effect if applied far from pivot.

In a lever, effort arm is the distance between: A) Load and effort B) Effort and fulcrum C) Fulcrum and load D) None Answer: B Explanation: The effort arm is the distance between the point of effort application and the fulcrum.

Levers reduce: A) Speed B) Energy C) Force required D) Friction Answer: C Explanation: Levers allow a smaller force to move a larger load by increasing the effort arm. Continuing with:

Chapter 5: Gravitation

The force of attraction between two objects is called: A) Magnetic force B) Electrostatic force C) Gravitational force D) Frictional force Answer: C Explanation: Gravitational force is the natural force of attraction between two masses.

Newton's law of gravitation states that: A) Force is proportional to the square of distance B) Force is proportional to mass C) Force is inversely proportional to square of distance D) Force is constant Answer: C Explanation: The gravitational force is inversely proportional to the square of the distance between the centers of two masses.

Gravitational force increases if: A) Masses decrease B) Distance increases C) Masses increase D) Distance is squared Answer: C Explanation: Greater masses exert greater gravitational attraction.

Unit of gravitational constant G is: A) Nm B) Nm²/kg C) Nm²/kg² D) N/kg Answer: C Explanation: G has the units Nm²/kg² based on its formula in Newton’s law: F=Gm1m2r2F = G \frac{m_1 m_2}{r^2}.

The value of G is: A) 9.8 m/s² B) 6.67 × 10⁻¹¹ Nm²/kg² C) 10 m/s² D) 6.67 × 10¹¹ Nm/kg² Answer: B Explanation: G is a universal constant equal to 6.67 × 10⁻¹¹ Nm²/kg².

The force that keeps planets in orbit is: A) Magnetic force B) Inertia C) Gravitational force D) Nuclear force Answer: C Explanation: Planets are held in orbit around the sun due to gravitational attraction.

The acceleration due to gravity on Earth is approximately: A) 10 m/s² B) 8.9 m/s² C) 6.67 m/s² D) 9.8 m/s² Answer: D Explanation: On Earth's surface, the average gravitational acceleration is 9.8 m/s².

Weight is defined as: A) Mass × distance B) Mass × velocity C) Mass × gravity D) Mass / gravity Answer: C Explanation: Weight is the force due to gravity and is calculated by: Weight = mass × g.

Weight is a: A) Scalar quantity B) Unitless quantity C) Vector quantity D) Constant Answer: C Explanation: Weight has both magnitude and direction (toward Earth's center), so it is a vector.

Which quantity remains same on moon and Earth? A) Weight B) Mass C) Gravitational force D) Gravitational field Answer: B Explanation: Mass is the amount of matter in an object and does not change with location.

The value of g decreases with: A) Height from Earth B) Increase in mass C) Decrease in radius D) Going toward poles Answer: A Explanation: As height increases from Earth's surface, gravity weakens.

g is maximum at: A) Poles B) Equator C) Center of Earth D) Moon Answer: A Explanation: Due to Earth’s shape, the gravitational acceleration is slightly greater at the poles.

Weight of an object in free fall becomes: A) Double B) Half C) Zero D) Maximum Answer: C Explanation: In free fall, the object is in weightlessness since the normal reaction force becomes zero.

The orbit of the moon is maintained by: A) Magnetic force B) Electrostatic force C) Inertia D) Earth’s gravity Answer: D Explanation: The moon orbits Earth due to Earth’s gravitational pull.

The greater the distance between objects, the gravitational force is: A) Greater B) Same C) Weaker D) None Answer: C Explanation: Gravitational force decreases rapidly as distance increases.

Which one is not affected by gravity? A) Satellite B) Free falling object C) Light D) Sound Answer: D Explanation: Sound needs a medium and doesn’t interact with gravity; gravity can bend light and pull matter.

An object thrown upward will have: A) Constant speed B) Decreasing velocity C) Increasing acceleration D) Zero acceleration Answer: B Explanation: As an object rises, gravity slows it down, decreasing its velocity until it stops momentarily.

The formula for gravitational force is: A) F=maF = ma B) F=Gm1m2r2F = G \frac{m_1 m_2}{r^2} C) F=mgF = mg D) F=mghF = mgh Answer: B Explanation: Newton’s universal law of gravitation uses this formula to find force between two masses.

Gravitational field strength is measured in: A) m/s B) N/kg C) J D) N/m Answer: B Explanation: Gravitational field strength is force per unit mass, measured in newtons per kilogram (N/kg).

Weightlessness is experienced when: A) Object is falling B) No gravity C) Object moves in air D) In rest Answer: A Explanation: In free fall, gravity is the only acting force; all internal support forces vanish, causing weightlessness.

A satellite moves in circular orbit due to: A) Balanced forces B) Gravitational force C) Centrifugal force D) Magnetic force Answer: B Explanation: The only force acting on a satellite in orbit is gravity, pulling it toward Earth.

The Earth's gravity pulls objects toward: A) Sky B) Outer space C) Center of Earth D) Poles Answer: C Explanation: Gravitational force always pulls objects toward the center of the Earth.

If mass of an object doubles, its weight becomes: A) Half B) Same C) Double D) Zero Answer: C Explanation: Weight = mass × gravity. If mass doubles, weight also doubles.

The force that causes falling apples is: A) Friction B) Gravitational force C) Centripetal force D) Electrostatic force Answer: B Explanation: Gravity pulls objects toward Earth’s surface, as observed by Newton.

The mass of Earth affects: A) Moon's light B) Gravity on Earth C) Orbit of sun D) None Answer: B Explanation: Earth’s mass directly determines the strength of its gravitational field.

Free fall occurs when only which force acts on a body? A) Friction B) Applied force C) Gravity D) Air resistance Answer: C Explanation: In free fall, gravity is the only force acting on an object.

The moon’s gravity is about: A) Same as Earth B) 1/6th of Earth's C) Double Earth D) Zero Answer: B Explanation: The moon’s gravity is about 1/6th that of Earth, which is why objects weigh less on the moon.

The instrument used to measure mass is: A) Spring balance B) Weighing machine C) Beam balance D) Thermometer Answer: C Explanation: A beam balance compares masses, which is independent of gravity.

Gravitational force is always: A) Attractive B) Repulsive C) Balanced D) Zero Answer: A Explanation: Gravitational force only attracts masses; it never repels.

Gravity is weakest on: A) Jupiter B) Earth C) Mars D) Moon Answer: D Explanation: Among these, the moon has the smallest mass and radius, hence weakest gravity. Continuing with:

Chapter 6: Work and Energy

Work is done when: A) Force is applied but no movement B) Object moves perpendicular to force C) Force causes displacement D) Object stays still Answer: C Explanation: Work is defined as force applied over a distance in the direction of the force.

SI unit of work is: A) Watt B) Newton C) Joule D) Erg Answer: C Explanation: Work is measured in joules (J); 1 joule = 1 newton × 1 meter.

Work done = A) Force × speed B) Force / distance C) Force × time D) Force × displacement × cosθ Answer: D Explanation: Work done depends on the component of force in the direction of displacement: W = F × d × cosθ.

If θ = 0°, then cosθ = A) 1 B) 0 C) −1 D) ∞ Answer: A Explanation: When force and displacement are in the same direction, θ = 0°, so cos(0°) = 1.

No work is done when: A) A book is lifted B) A box is pushed C) A force is applied but no movement occurs D) A car is moving Answer: C Explanation: Work requires displacement. If there’s no movement, no work is done.

If displacement is perpendicular to force, then work done is: A) Maximum B) Minimum C) Zero D) Infinite Answer: C Explanation: W = F × d × cosθ. If θ = 90°, cos(90°) = 0, so work = 0.

Power is defined as: A) Work × time B) Work / time C) Force / time D) Energy × distance Answer: B Explanation: Power is the rate at which work is done or energy is transferred.

SI unit of power is: A) Joule B) Newton C) Watt D) Erg Answer: C Explanation: Power is measured in watts (W), where 1 watt = 1 joule/second.

One kilowatt = A) 10 W B) 100 W C) 1000 W D) 10000 W Answer: C Explanation: 1 kilowatt = 1000 watts.

A body has energy if it can: A) Fall B) Change color C) Do work D) Increase temperature Answer: C Explanation: Energy is defined as the capacity to do work.

SI unit of energy is: A) Erg B) Newton C) Joule D) Watt Answer: C Explanation: Energy is measured in joules (J), same as work.

Kinetic energy depends on: A) Mass only B) Speed only C) Mass and speed D) Volume Answer: C Explanation: Kinetic energy = ½mv², so it depends on both mass and velocity.

The formula for kinetic energy is: A) mv B) ½mv² C) mgh D) mg Answer: B Explanation: KE = ½mv² — energy possessed by a body in motion.

Potential energy is due to: A) Speed B) Position C) Temperature D) Shape Answer: B Explanation: PE = mgh, energy due to position in a gravitational field.

A body at height has: A) Kinetic energy B) Thermal energy C) Electrical energy D) Potential energy Answer: D Explanation: Being elevated, the body possesses gravitational potential energy.

Work-energy principle states: A) Work done = power × time B) Work = force / displacement C) Work = change in energy D) Energy is constant Answer: C Explanation: The work done on an object equals the change in its energy.

Energy cannot be: A) Transferred B) Converted C) Created or destroyed D) Measured Answer: C Explanation: According to the law of conservation of energy, energy can only change form, not be created or destroyed.

Unit of commercial energy is: A) Joule B) Erg C) Kilowatt-hour D) Calorie Answer: C Explanation: Energy used by electric companies is measured in kilowatt-hours (kWh).

One kilowatt-hour = A) 1000 J B) 3600 J C) 3.6 × 10⁶ J D) 36 × 10⁶ J Answer: C Explanation: 1 kWh = 1000 W × 3600 s = 3.6 × 10⁶ J.

A moving car possesses: A) Potential energy B) Kinetic energy C) No energy D) Electrical energy Answer: B Explanation: Due to its motion, the car has kinetic energy.
A stretched bow has: A) Heat energy B) Potential energy C) Chemical energy D) Electrical energy Answer: B Explanation: The tension in the bow stores elastic potential energy.

Mechanical energy is the sum of: A) Heat and sound B) Light and thermal C) Kinetic and potential energy D) Work and pressure Answer: C Explanation: Mechanical energy = KE + PE — energy due to motion and position.

Which one is a form of kinetic energy? A) Water stored in dam B) A rock on a hill C) Wind D) Compressed spring Answer: C Explanation: Wind has moving air particles — kinetic energy.

What is conserved in all energy conversions? A) Mass B) Volume C) Energy D) Speed Answer: C Explanation: Energy is conserved — total energy remains constant though form may change.

Solar panels convert solar energy into: A) Kinetic energy B) Chemical energy C) Electrical energy D) Potential energy Answer: C Explanation: Solar cells convert sunlight directly into electrical energy.

Hydroelectric power uses: A) Chemical energy B) Nuclear energy C) Gravitational potential energy D) Light energy Answer: C Explanation: Water at a height has PE, which converts to KE and then electrical energy.

Work is positive when: A) Force is opposite to displacement B) Force is perpendicular C) Force is in direction of displacement D) No displacement Answer: C Explanation: Work is positive when force acts in the same direction as displacement.

Negative work is done when: A) Displacement is in direction of force B) Force and displacement are opposite C) Force and displacement are perpendicular D) No force applied Answer: B Explanation: If displacement is opposite to applied force, work is negative (e.g., friction).

A man lifts a 10 kg object to 2 m. Work done is: A) 20 J B) 100 J C) 196 J D) 98 J Answer: D Explanation: Work = mgh = 10 × 9.8 × 1 = 98 J.

Which energy form is used in food? A) Nuclear energy B) Electrical energy C) Chemical energy D) Sound energy Answer: C Explanation: Food contains stored chemical energy used by the body. Continuing with:

Chapter 7: Thermal Properties of Matter

Heat is a form of: A) Matter B) Force C) Energy D) Pressure Answer: C Explanation: Heat is a form of energy that flows from a hotter body to a cooler one.

SI unit of heat is: A) Calorie B) Joule C) Watt D) Degree Answer: B Explanation: Although calories are commonly used, the SI unit for heat is the joule (J).

Temperature is a measure of: A) Total heat B) Heat capacity C) Hotness or coldness D) Molecular mass Answer: C Explanation: Temperature indicates how hot or cold a body is, relating to the average kinetic energy of particles.

SI unit of temperature is: A) Celsius B) Fahrenheit C) Kelvin D) Calorie Answer: C Explanation: The SI unit of temperature is Kelvin (K), based on absolute zero.

The instrument used to measure temperature is: A) Barometer B) Thermometer C) Hygrometer D) Manometer Answer: B Explanation: A thermometer is used to measure temperature.

The process by which heat transfers through solids is: A) Radiation B) Convection C) Conduction D) Fusion Answer: C Explanation: In solids, heat is mainly transferred via conduction.

Convection mainly occurs in: A) Solids B) Liquids and gases C) Metals D) Vacuum Answer: B Explanation: Convection is the transfer of heat through fluids (liquids and gases) by movement of particles.

Radiation does not require: A) Heat B) Medium C) Source D) Particles Answer: B Explanation: Radiation transfers heat through electromagnetic waves and doesn’t need a medium.

Boiling point of pure water in Celsius is: A) 50°C B) 0°C C) 100°C D) 37°C Answer: C Explanation: At sea level, pure water boils at 100°C.

Melting point of ice in Kelvin is: A) 100 K B) 0 K C) 273 K D) 373 K Answer: C Explanation: 0°C = 273 K, which is the melting point of ice in Kelvin scale.

Heat capacity is defined as: A) Heat per mass B) Heat per time C) Heat required to raise temperature of a body by 1°C D) Mass × temperature Answer: C Explanation: Heat capacity is the amount of heat needed to raise the temperature of the whole object by 1°C.

Specific heat capacity formula is: A) Q = mc² B) Q = mct C) Q = mcΔT D) Q = mt/c Answer: C Explanation: Q = mcΔT, where Q is heat, m is mass, c is specific heat capacity, and ΔT is temperature change.

Which material is a good conductor of heat? A) Plastic B) Glass C) Wood D) Copper Answer: D Explanation: Copper is a metal and an excellent conductor of heat.

Which material is a poor conductor of heat? A) Aluminum B) Silver C) Rubber D) Steel Answer: C Explanation: Rubber is an insulator and poor conductor of heat.

Which is best method of heat transfer in vacuum? A) Conduction B) Convection C) Radiation D) None Answer: C Explanation: Only radiation can transfer heat in a vacuum (e.g., sunlight reaching Earth).

Unit of specific heat capacity is: A) J/kg B) J/kg·K C) W/kg D) N/kg Answer: B Explanation: Specific heat capacity is measured in joules per kilogram per kelvin (J/kg·K).

Water is used as a coolant because it has: A) High boiling point B) High density C) High specific heat capacity D) High pressure Answer: C Explanation: Water absorbs a lot of heat with little temperature change due to its high specific heat capacity.

Latent heat is the heat: A) That changes temperature B) Absorbed or released during phase change C) Used in conduction D) Lost by cooling Answer: B Explanation: Latent heat is the energy absorbed or released during a change of state (e.g., melting) without temperature change.

Heat energy flows from: A) Cold to hot B) Low pressure to high pressure C) Hot to cold D) Same to same Answer: C Explanation: Heat always flows from a body at higher temperature to one at lower temperature.

Thermal expansion means: A) Increase in density B) Increase in length, area, or volume due to heat C) Decrease in temperature D) Contraction due to cold Answer: B Explanation: Most materials expand when heated — this is called thermal expansion.

The black surface is a: A) Poor absorber B) Good reflector C) Good absorber and emitter of radiation D) Poor radiator Answer: C Explanation: Black surfaces absorb and emit radiation efficiently.

Land heats up and cools down: A) Slower than water B) Faster than water C) Same as water D) Not at all Answer: B Explanation: Land has a lower specific heat capacity than water, so it heats and cools faster.

Which device uses thermal expansion of liquids? A) Barometer B) Thermometer C) Voltmeter D) Hygrometer Answer: B Explanation: Thermometers use the expansion of liquids (like mercury or alcohol) with temperature.

When ice melts at 0°C, temperature: A) Increases B) Decreases C) Remains constant D) Becomes negative Answer: C Explanation: During melting, heat is used to change state, so temperature remains constant.

During boiling, temperature of water: A) Increases rapidly B) Decreases C) Remains constant D) Varies randomly Answer: C Explanation: While boiling, temperature stays at 100°C until all water turns to steam.

Which material expands the most when heated? A) Solids B) Liquids C) Gases D) Metals Answer: C Explanation: Gases expand more than solids or liquids when heated due to weaker intermolecular forces.

Change in state occurs at: A) Any temperature B) Specific temperature C) Random intervals D) Continuous variation Answer: B Explanation: Each substance changes state at a specific melting or boiling point.

Conduction is fastest in: A) Solids B) Liquids C) Gases D) Vacuum Answer: A Explanation: In solids, tightly packed particles conduct heat faster through vibrations.

Evaporation causes cooling because: A) Temperature increases B) Molecules stick together C) Fastest molecules leave, lowering average kinetic energy D) Heat is absorbed Answer: C Explanation: Fast-moving molecules escape, leaving behind slower ones, reducing the average temperature.

Heat energy required to change 1 kg of a solid into liquid without changing temperature is called: A) Latent heat of vaporization B) Specific heat C) Latent heat of fusion D) Thermal energy Answer: C Explanation: This is the latent heat of fusion — the heat needed to melt 1 kg of a solid at its melting point. Continuing with:

Chapter 8: Electrostatics

Electrostatics is the study of: A) Current electricity B) Magnetic fields C) Stationary electric charges D) Moving electric charges Answer: C Explanation: Electrostatics deals with the behavior of stationary electric charges and the forces they exert.

Like charges: A) Attract each other B) Have no effect C) Repel each other D) Become neutral Answer: C Explanation: Charges with the same sign repel; opposite charges attract.

The SI unit of electric charge is: A) Ampere B) Coulomb C) Volt D) Ohm Answer: B Explanation: The standard unit of electric charge is the coulomb (C).

Charge on an electron is: A) +1.6 × 10⁻¹⁹ C B) −1.6 × 10⁻¹⁹ C C) 0 D) 1 C Answer: B Explanation: The electron carries a negative elementary charge of −1.6 × 10⁻¹⁹ C.

Protons carry: A) Negative charge B) No charge C) Positive charge D) Double negative charge Answer: C Explanation: A proton carries a positive charge equal in magnitude to that of the electron.

Charging a body by rubbing is called: A) Induction B) Conduction C) Friction D) Radiation Answer: C Explanation: Friction between objects causes transfer of electrons, resulting in static charge.

A body becomes positively charged when it: A) Gains electrons B) Gains protons C) Loses electrons D) Loses protons Answer: C Explanation: Losing negatively charged electrons leaves the body positively charged.

A negatively charged body has: A) Extra protons B) Less neutrons C) Extra electrons D) No charge Answer: C Explanation: An excess of electrons causes a body to be negatively charged.

The device used to detect electric charge is: A) Voltmeter B) Electroscope C) Ammeter D) Galvanometer Answer: B Explanation: An electroscope detects the presence and nature of electric charges.

Charging without touching is called: A) Friction B) Conduction C) Induction D) Radiation Answer: C Explanation: In induction, a charged object induces opposite charge in a nearby conductor without direct contact.

Coulomb's law applies to: A) Moving charges B) Stationary charges C) Magnetic poles D) Circuits Answer: B Explanation: Coulomb's law describes the force between stationary (electrostatic) charges.

According to Coulomb's law, force between charges is: A) Directly proportional to distance B) Inversely proportional to distance C) Directly proportional to square of distance D) Inversely proportional to square of distance Answer: D Explanation: F∝1r2F \propto \frac{1}{r^2}, where r is the distance between charges.

Electrostatic force increases when: A) Distance increases B) Charges decrease C) Distance decreases D) Temperature increases Answer: C Explanation: As distance between charges decreases, the electrostatic force increases.

Electrostatic force acts along: A) Circular path B) Straight line joining charges C) Magnetic lines D) Field lines only Answer: B Explanation: Electrostatic force is a central force and acts along the line joining the charges.

SI unit of electrostatic force is: A) Coulomb B) Newton C) Volt D) Joule Answer: B Explanation: Since force is being measured, its SI unit is the newton (N).

Two similar charges brought near each other will: A) Attract B) Repel C) Combine D) Become neutral Answer: B Explanation: Like charges repel due to electrostatic repulsion.

If one charge is doubled, force becomes: A) Half B) Double C) Four times D) Unchanged Answer: B Explanation: F∝q1F \propto q_1, so doubling one charge doubles the force.

If both charges are doubled, the force becomes: A) Double B) Triple C) Four times D) Half Answer: C Explanation: F∝q1q2F \propto q_1 q_2, so doubling both charges quadruples the force.

If distance between charges is doubled, force becomes: A) Half B) Double C) One-fourth D) Four times Answer: C Explanation: F∝1r2F \propto \frac{1}{r^2}, so doubling distance reduces force to one-fourth.

Electric field is defined as: A) Force per unit area B) Force per unit charge C) Work per unit charge D) Energy per second Answer: B Explanation: E=FqE = \frac{F}{q}, where E is the electric field and q is the test charge.

Unit of electric field is: A) N B) N/C C) J D) V Answer: B Explanation: Electric field strength is measured in newtons per coulomb (N/C).

Electric field lines originate from: A) Negative charge B) Both charges C) Positive charge D) Zero charge Answer: C Explanation: Field lines begin on positive charges and end on negative charges.

Electric field is strongest where field lines are: A) Curved B) Far apart C) Parallel D) Closely spaced Answer: D Explanation: Closer field lines represent stronger electric fields.

Conductors allow: A) Free movement of electrons B) Blocking of charge C) No electric current D) Heat transfer only Answer: A Explanation: Conductors have free electrons that can move and conduct electric charge.

Insulators do not allow: A) Light to pass B) Electrons to move freely C) Heat conduction D) Magnetism Answer: B Explanation: Insulators restrict free electron flow and resist charge movement.

Earthing is done to: A) Store charges B) Block electricity C) Prevent shock D) Increase resistance Answer: C Explanation: Earthing provides a safe path for excess charge, preventing electric shocks.

In charging by induction, the charged body: A) Loses charge B) Gains charge C) Remains unchanged D) Disappears Answer: C Explanation: The inducing body never transfers charge in induction; it only rearranges charges in the other body.

Spark is caused by: A) Light B) Sudden release of heat C) Sudden discharge of static charge D) Magnetic field Answer: C Explanation: Spark results when static charge builds up and suddenly discharges through air.

Lightning is a natural example of: A) Electric circuit B) Electrostatics C) Magnetic field D) Conduction Answer: B Explanation: Lightning is the discharge of static electricity between clouds or between clouds and the Earth.

When a charged rod touches a neutral object: A) No effect B) Object becomes charged by conduction C) Object is grounded D) Object is destroyed Answer: B Explanation: Contact (conduction) transfers some of the charge, making the neutral object charged. Continuing with:

Chapter 9: Current Electricity

Electric current is defined as: A) Flow of protons B) Flow of neutrons C) Flow of electrons D) Flow of energy Answer: C Explanation: Electric current is the flow of electrons through a conductor.

The SI unit of electric current is: A) Volt B) Coulomb C) Ohm D) Ampere Answer: D Explanation: The standard unit of current is the ampere (A), defined as 1 coulomb of charge per second.

The device used to measure current is: A) Voltmeter B) Ammeter C) Ohmmeter D) Electroscope Answer: B Explanation: An ammeter measures electric current and is always connected in series in a circuit.

Current = A) Voltage / resistance B) Charge / time C) Power / voltage D) Energy × time Answer: B Explanation: Electric current (I) is the rate of flow of charge: I=QtI = \frac{Q}{t}.

One ampere equals: A) 1 coulomb / 1 hour B) 1 volt / 1 second C) 1 coulomb / 1 second D) 1 ohm / 1 volt Answer: C Explanation: 1 A = 1 C/s, meaning one coulomb of charge flows per second.

The SI unit of voltage is: A) Ampere B) Ohm C) Volt D) Watt Answer: C Explanation: Voltage (potential difference) is measured in volts (V).

Voltage is defined as: A) Current per time B) Energy per charge C) Charge per energy D) Resistance per time Answer: B Explanation: Voltage = WQ\frac{W}{Q}, where W is work (energy), Q is charge.

Ohm's law states: A) I = V²R B) V = IR C) R = VI D) V = I²R Answer: B Explanation: Ohm's law: Voltage across a conductor is directly proportional to current if temperature is constant.

Resistance is defined as: A) Opposition to flow of electrons B) Energy loss C) Power consumption D) Charge storage Answer: A Explanation: Resistance opposes the flow of electric current in a conductor.

SI unit of resistance is: A) Volt B) Ohm C) Joule D) Watt Answer: B Explanation: Resistance is measured in ohms (Ω).

Device used to measure voltage is: A) Ammeter B) Voltmeter C) Thermometer D) Electrometer Answer: B Explanation: A voltmeter is connected in parallel across two points to measure potential difference.

Resistance depends on: A) Mass B) Area, length, material C) Weight D) Power Answer: B Explanation: Resistance depends on the conductor’s length (l), cross-sectional area (A), and resistivity (ρ): R=ρlAR = \rho \frac{l}{A}.

Current is directly proportional to: A) Resistance B) Voltage C) Temperature D) Power Answer: B Explanation: From Ohm's law: I=VRI = \frac{V}{R}, so current increases with voltage if resistance is constant.

If resistance doubles and voltage remains constant, current becomes: A) Half B) Double C) Same D) Zero Answer: A Explanation: I=VRI = \frac{V}{R}. If R doubles, I is halved.

Power in an electric circuit is given by: A) V × I B) I / V C) V / R D) V + I Answer: A Explanation: Electric power: P=VIP = VI, product of voltage and current.

The energy used = A) Voltage × resistance B) Power × time C) Current / time D) Voltage / time Answer: B Explanation: Energy consumed = Power × time = VI×tVI \times t

The instrument that opens or closes a circuit is: A) Resistor B) Battery C) Switch D) Ammeter Answer: C Explanation: A switch is used to control the flow of current by opening or closing the circuit.

The current in a series circuit is: A) Different at each point B) Zero C) Same at every point D) Random Answer: C Explanation: In series, current remains constant throughout the circuit.

In a parallel circuit, voltage across each branch is: A) Zero B) Same C) Different D) Inversely proportional Answer: B Explanation: In parallel, all branches have the same voltage.

Which material is a good conductor? A) Plastic B) Glass C) Copper D) Rubber Answer: C Explanation: Copper has low resistance and allows electrons to flow easily.

A fuse is used for: A) Increasing resistance B) Preventing short circuits C) Storing charge D) Controlling temperature Answer: B Explanation: A fuse melts when excessive current flows, protecting the circuit.

Electric energy is measured in: A) Watts B) Joules C) Volts D) Ohms Answer: B Explanation: Energy is measured in joules; in electrical terms, E = Power × time.

Which component opposes current in a circuit? A) Voltmeter B) Resistor C) Switch D) Cell Answer: B Explanation: A resistor limits or opposes the flow of current.

What does a battery do? A) Opposes current B) Stores current C) Converts chemical energy to electrical energy D) Measures voltage Answer: C Explanation: A battery provides electrical energy by chemical reactions inside it.

Current in a conductor flows from: A) Negative to positive B) Positive to negative C) High resistance to low D) Ground to terminal Answer: B Explanation: By convention, current flows from positive to negative terminal, though electrons move oppositely.

Which wire has least resistance? A) Thin and long B) Thick and long C) Thick and short D) Thin and short Answer: C Explanation: Resistance is low in thick, short wires.

Electric charge is measured in: A) Volts B) Joules C) Coulombs D) Amperes Answer: C Explanation: Coulomb (C) is the SI unit for electric charge.

In parallel circuits, total resistance is: A) Sum of all resistances B) Higher than any branch C) Less than smallest resistor D) Equal to largest resistor Answer: C Explanation: In parallel, total resistance is always less than the smallest resistor.

A device with resistance converts electrical energy into: A) Magnetic energy B) Heat energy C) Kinetic energy D) Light only Answer: B Explanation: Resistors dissipate electrical energy as heat.

The potential difference causes: A) Resistance B) Heat C) Flow of current D) Power Answer: C Explanation: A potential difference (voltage) provides the driving force that causes current to flow. Continuing with:

Chapter 10: Basic Electronics

Electronics deals with the study of: A) Motion B) Resistance C) Flow of electrons in vacuum or semiconductors D) Light energy Answer: C Explanation: Electronics involves the control and behavior of electrons, especially in semiconductors and circuits.

A semiconductor lies between: A) Insulators and metals B) Conductors and magnets C) Non-metals and gases D) Insulators and liquids Answer: A Explanation: Semiconductors have electrical properties intermediate between conductors and insulators.

The most commonly used semiconductor is: A) Copper B) Silver C) Silicon D) Iron Answer: C Explanation: Silicon is abundant, stable, and widely used in electronic devices.

The pure form of a semiconductor is called: A) Doped B) Intrinsic C) Impure D) Ionized Answer: B Explanation: An intrinsic semiconductor is a pure form with equal numbers of electrons and holes.

The process of adding impurities to semiconductors is called: A) Conducting B) Diffusion C) Doping D) Heating Answer: C Explanation: Doping adds controlled impurities to change the conductivity of semiconductors.

Doping with pentavalent atoms creates: A) P-type B) Intrinsic type C) N-type D) Metallic Answer: C Explanation: Pentavalent atoms (5 valence electrons) contribute free electrons, forming n-type semiconductors.

Trivalent impurities form: A) N-type B) Intrinsic C) P-type D) Metallic Answer: C Explanation: Trivalent atoms create "holes" and form p-type semiconductors.

A hole is: A) A missing atom B) A proton C) A position of missing electron D) A negative charge Answer: C Explanation: A hole is the absence of an electron in a covalent bond and acts like a positive charge.

A p-n junction is formed by joining: A) Two conductors B) A metal and non-metal C) P-type and n-type semiconductors D) Two p-type semiconductors Answer: C Explanation: A p-n junction is created by joining p-type and n-type semiconductors.

A p-n junction allows current to flow: A) In both directions B) Only when reversed C) In one direction only D) Not at all Answer: C Explanation: The p-n junction diode conducts in one direction (forward-biased).

The region around the p-n junction with no free charges is: A) Conduction region B) Depletion region C) Base region D) Collector region Answer: B Explanation: The depletion region is formed where mobile carriers are depleted near the junction.

The device that allows current in one direction only is: A) Resistor B) Diode C) Capacitor D) Transistor Answer: B Explanation: A diode permits current flow in one direction and blocks it in the reverse.

Diodes are mainly used for: A) Power supply B) Amplification C) Rectification D) Filtration Answer: C Explanation: Diodes convert alternating current (AC) to direct current (DC), a process known as rectification.

The device used to amplify weak signals is: A) Resistor B) Diode C) Transistor D) Capacitor Answer: C Explanation: Transistors are key components in amplification circuits.

A transistor has how many layers of semiconductors? A) 1 B) 2 C) 3 D) 4 Answer: C Explanation: A transistor has three semiconductor layers and two junctions (e.g., NPN or PNP types).

Which of the following is not a part of a transistor? A) Base B) Collector C) Amplifier D) Emitter Answer: C Explanation: Amplifier is a function, not a transistor part. The three parts are emitter, base, and collector.

The input of a transistor is applied between: A) Emitter and base B) Collector and emitter C) Base and collector D) None Answer: A Explanation: Input is between base and emitter; output is taken across collector and emitter.

A transistor in common emitter configuration gives: A) No amplification B) Voltage amplification C) Only resistance D) No current Answer: B Explanation: In the common emitter configuration, the transistor provides voltage and current amplification.

Which electronic component stores electric charge? A) Diode B) Capacitor C) Transistor D) Resistor Answer: B Explanation: A capacitor stores electric charge and releases it when needed.

Which component opposes change in current? A) Diode B) Transistor C) Inductor D) Capacitor Answer: C Explanation: An inductor resists changes in current, storing energy in its magnetic field.

In full-wave rectification, output is obtained: A) Once per cycle B) Twice per cycle C) Constantly D) Only for positive cycles Answer: B Explanation: A full-wave rectifier inverts both halves of AC, providing output in both directions.

The output of a half-wave rectifier is: A) Full sine wave B) Pulsating DC C) Constant DC D) Zero Answer: B Explanation: A half-wave rectifier allows only one half of the AC cycle through, producing a pulsating DC output.

Which of these converts AC to DC? A) Transistor B) Diode C) Transformer D) Inductor Answer: B Explanation: Diodes are essential in converting AC to DC in power supplies.

NPN transistor has: A) Two p layers B) Two n layers C) One p, one n D) No layers Answer: B Explanation: NPN transistors have two n-type and one p-type layer.

A transistor works as a switch when: A) Always on B) Fully on or fully off C) In forward bias only D) Used in voltage regulator Answer: B Explanation: Transistors operate as switches when they alternate between cutoff (off) and saturation (on) states.

Output of rectifier is made smooth using a: A) Diode B) Resistor C) Capacitor D) Switch Answer: C Explanation: Capacitors filter out ripples from the rectified output to make it smoother.

Current amplification factor (β) of a transistor is: A) Ratio of collector current to base current B) Emitter to collector current C) Voltage ratio D) Current minus voltage Answer: A Explanation: β=ICIB\beta = \frac{I_C}{I_B}, where ICI_C is collector current, and IBI_B is base current.

In NPN transistor, current flows from: A) Emitter to collector B) Collector to emitter C) Base to emitter D) Collector to base Answer: A Explanation: In NPN, electrons flow from emitter to collector.

The function of emitter is to: A) Control voltage B) Collect charge C) Emit majority charge carriers D) Store energy Answer: C Explanation: The emitter emits majority charge carriers into the base.

Diode is used in: A) Transformers B) Amplifiers C) Rectifiers D) Filters Answer: C Explanation: Diodes are key components in rectifier circuits that convert AC into DC.

Computer

Chapter 1: Problem Solving and Algorithm Designing

The first step in problem solving is: A) Designing the program B) Writing the code C) Understanding the problem D) Running the program Explanation: Before designing or coding, the problem must be clearly understood to identify what needs solving.

A finite set of instructions to solve a problem is called: A) Flowchart B) Code C) Algorithm D) Program Explanation: An algorithm is a step-by-step method used to solve a problem logically.

The graphical representation of an algorithm is called: A) Syntax tree B) Flowchart C) Pseudocode D) Block diagram Explanation: Flowcharts use symbols to represent the logical flow of steps in an algorithm.

Which of the following is NOT a characteristic of a good algorithm? A) Clarity B) Ambiguity C) Effectiveness D) Finiteness Explanation: A good algorithm must be unambiguous, clear, and must finish in finite steps.

A parallelogram in a flowchart is used for: A) Process B) Decision C) Input/Output D) Loop Explanation: Input and output operations are represented by a parallelogram.

A diamond symbol in a flowchart represents: A) Start B) Output C) Decision D) Process Explanation: Decisions (Yes/No or True/False) are represented by a diamond shape.

A rectangle in a flowchart represents: A) Process B) Decision C) Input D) Output Explanation: A process or operation is shown using a rectangle.

Which of the following is used to describe an algorithm in plain language? A) Flowchart B) Syntax C) Pseudocode D) Compiler Explanation: Pseudocode explains algorithmic logic in simple, structured language without programming syntax.

A good algorithm should have: A) Infinite steps B) Finite steps C) Random structure D) Variable length Explanation: Algorithms must be finite to ensure the problem is solved in a limited time.

A problem solving approach in computer science is called: A) Typing B) Algorithmic thinking C) Compilation D) Debugging Explanation: Algorithmic thinking involves breaking problems into steps that a computer can solve.

Which of the following is used for decision making in flowcharts? A) Rectangle B) Diamond C) Oval D) Circle Explanation: Decisions in logic (e.g., if-else) are represented by diamonds.

An algorithm must: A) Run forever B) Produce at least one result C) Be unclear D) Ignore logic Explanation: Algorithms are goal-oriented and must produce a result or solution.

In a flowchart, the terminator symbol (start/end) is: A) Rectangle B) Diamond C) Oval D) Parallelogram Explanation: Ovals mark the beginning and end of a flowchart.

What is the main purpose of an algorithm? A) To draw diagrams B) To solve problems logically C) To calculate speed D) To write code directly Explanation: Algorithms help solve problems step-by-step before coding begins.

A loop structure in algorithms is used to: A) Repeat steps B) Make decisions C) Start execution D) Stop the program Explanation: Loops allow repeating a sequence until a condition is met.

The step-by-step plan of solving a problem is called: A) Debugging B) Algorithm C) Coding D) Logic gate Explanation: An algorithm is the organized series of steps to solve a problem.

Which symbol is used to represent flow of control in a flowchart? A) Circle B) Box C) Arrow D) Diamond Explanation: Arrows indicate the sequence of steps in a flowchart.

Which of the following is NOT a benefit of flowcharts? A) Better understanding B) Increases coding speed only C) Error detection D) Communication tool Explanation: Flowcharts aid in logic and communication but don't directly speed up coding.

A dry run of an algorithm helps in: A) Adding code B) Checking logic manually C) Installing software D) Upgrading hardware Explanation: A dry run manually traces an algorithm to verify its correctness.

What is the correct order of problem-solving steps? A) Understand → Plan → Code → Test B) Code → Plan → Test → Understand C) Test → Understand → Code → Plan D) Code → Test → Understand → Run Explanation: Correct order is understanding, planning (algorithm), coding, and then testing.

Which tool is best for communicating the solution logic to others? A) Code B) Flowchart C) Hardware D) Monitor Explanation: Flowcharts visually communicate logic clearly and simply.

Which of the following should be avoided in algorithm writing? A) Simplicity B) Unclear steps C) Definite instructions D) Termination Explanation: Unclear steps lead to confusion and incorrect solutions.

Why are algorithms useful before programming? A) Reduce hardware usage B) Help structure logic clearly C) Save typing time D) Increase program size Explanation: Algorithms outline logic before implementation, reducing confusion.

An algorithm should always: A) Produce the correct output B) Work with any hardware C) Include pictures D) Require long instructions Explanation: Accuracy of output is a key requirement of an algorithm.

Which of these symbols is never used in flowcharts? A) Diamond B) Oval C) Rectangle D) Triangle Explanation: Triangle is not a standard flowchart symbol.

What helps break a problem into smaller tasks? A) Printer B) Program C) Algorithm design D) Scanner Explanation: Algorithm design helps divide a complex problem into smaller manageable steps.

Decision-making in algorithms is based on: A) Guess B) Conditions C) Timing D) Input size Explanation: Decisions are made using conditional logic (e.g., IF statements).

Which of these is a tool for planning logic before coding? A) Flowchart B) Hard disk C) RAM D) CPU Explanation: Flowcharts help design logic before implementing in code.

Why should an algorithm be simple? A) To look short B) To make it easy to understand and debug C) To avoid flowcharts D) To reduce input Explanation: Simplicity ensures clarity, making debugging and implementation easier.

Which of the following is essential before converting logic into a program? A) Designing an algorithm and flowchart B) Typing fast C) Installing compiler D) Creating a folder Explanation: Algorithm and flowchart are crucial planning tools before coding.

Chapter 2: Basics of Programming in C++

C++ is a: A) Functional language B) Object-oriented programming language C) Machine-level language D) Markup language Explanation: C++ supports object-oriented features like classes and inheritance.
The extension of a C++ source file is usually: A) .txt B) .java C) .cpp D) .exe Explanation: C++ programs are saved with the .cpp extension before compilation.
The smallest individual unit in a C++ program is called: A) Constant B) Token C) Loop D) Statement Explanation: Tokens are the smallest units like keywords, identifiers, and symbols.
A group of instructions given to the computer is known as: A) Command B) Program C) Compiler D) Header Explanation: A program is a sequence of instructions written to perform a task.
The function where execution of a C++ program begins is: A) start() B) open() C) execute() D) main() Explanation: main() is the entry point of every C++ program.
Which of these is a correct comment in C++? A) B) \* comment \* C) ## comment D) // comment Explanation: // is used for single-line comments in C++.
Which header file is used for input and output operations? A) iostream.h B) stdio.h C) conio.h D) iostream Explanation: In modern C++, #include is used for input and output streams.
The operator << is used for: A) Assignment B) Output (in cout) C) Input (in cin) D) Comments Explanation: << is the insertion operator used with cout.
The operator >> is used with: A) cout B) cin C) return D) main Explanation: >> is the extraction operator used to get input from the user via cin.
The keyword used to declare a variable is: A) define B) int C) header D) get Explanation: int is a data type keyword that also acts as a declaration for integer variables.
Which symbol ends a statement in C++? A) : B) , C) ' D) ; Explanation: Every statement in C++ ends with a semicolon (;).
Which of the following is not a valid data type in C++? A) float B) int C) char D) real Explanation: real is not a valid C++ data type; float is used for decimal values.
What is the result of 5 / 2 in C++ (both integers)? A) 2.5 B) 2 C) 0 D) 3 Explanation: Integer division in C++ truncates the decimal part, so 5 / 2 = 2.
What will cout << "Hello"; do? A) Display Hello on screen B) Take input C) Store a value D) Cause an error Explanation: cout displays the message on the screen using the insertion operator.
Which character is used to include header files? A) % B) # C) & D) @ Explanation: The # symbol is used in preprocessor directives like #include.
A variable must be ______ before use. A) Executed B) Declared C) Assigned D) Output Explanation: All variables must be declared with a data type before use.
The function cin is used for: A) Output B) Storing C) Input D) Returning values Explanation: cin (character input) takes input from the user.
What is the output of cout << 3 + 2;? A) 32 B) 5 C) 3+2 D) Error Explanation: C++ evaluates the expression 3 + 2 and displays 5.
Keywords in C++ are: A) User-defined B) Predefined and reserved C) Changeable D) Ignored by compiler Explanation: Keywords are reserved words that have special meaning in C++.
The term "syntax" refers to: A) Variable name B) Execution order C) Rules of writing statements D) Loop count Explanation: Syntax defines how instructions must be written correctly in a language.
If you forget to put ; at the end of a statement, you get a: A) Warning B) Logic error C) Syntax error D) Run-time error Explanation: Missing semicolon causes a syntax error during compilation.
Which data type is used to store characters? A) int B) char C) float D) bool Explanation: char is used for single character storage.
Which of the following is a valid identifier in C++? A) 2num B) float C) user_name D) char Explanation: user_name is a valid identifier; it does not start with a digit and is not a keyword.
To get a new line in output, use: A) /line B) \n C) endl() D) exit Explanation: \n is the escape sequence for a new line in strings.
What does return 0; indicate in main()? A) Program error B) Wrong output C) Successful termination D) Function call Explanation: return 0; means the program ended successfully.
How many times is main() used in a C++ program? A) Once B) Twice C) Optional D) As many as needed Explanation: Only one main() function is allowed and required per C++ program.
What is the default value of an uninitialized integer in C++? A) 1 B) -1 C) Garbage value D) 0 Explanation: Local uninitialized variables contain garbage values in C++.
C++ was developed by: A) James Gosling B) Bjarne Stroustrup C) Dennis Ritchie D) Bill Gates Explanation: Bjarne Stroustrup developed C++ as an extension of C.
C++ supports which programming paradigm? A) Procedural only B) Both procedural and object-oriented C) Assembly D) Modular only Explanation: C++ supports multiple paradigms including object-oriented and procedural.
Which of the following is not a valid operator in C++? A) + B) := C) - D) / Explanation: := is not used in C++; it is used in languages like Pascal.

Chapter 3: Input/Output Handling in C++

Which header file is required for input and output operations in C++? A) stdio.h B) conio.h C) iostream D) math.h Explanation: The iostream header file is used for input and output operations in C++.

What is the function used to display output in C++? A) input() B) scan() C) cout D) display() Explanation: The cout function is used to output data to the screen.

What is the function used to take input from the user in C++? A) output() B) cin C) scan() D) get() Explanation: The cin function is used to accept input from the user.

The << operator is used for: A) Assignment B) Output C) Input D) Arithmetic operations Explanation: The << operator is the insertion operator used for output with cout.

The >> operator is used for: A) Assignment B) Input C) Output D) Data manipulation Explanation: The >> operator is the extraction operator used with cin for input.

Which of the following is the correct way to display a string? A) cout > "Hello World"; B) cout << "Hello World"; C) output << "Hello World"; D) cout - "Hello World"; Explanation: The << operator is used to send the output to cout.

Which of the following statements correctly reads an integer into the variable x? A) cin << x; B) cin >> x; C) cin - x; D) input >> x; Explanation: The >> operator is used with cin to read input.

To insert a new line after the output, which command is used? A) cout << endl(); B) cout << endl; C) cout << "n"; D) cout << "newline"; Explanation: The endl manipulator is used to insert a new line and flush the output buffer.

What is the purpose of the flush function in C++? A) To stop the program B) To erase the output buffer C) To add a new line D) To flush the output buffer Explanation: flush is used to flush the output buffer and ensure data is printed immediately.

Which function is used to clear the input buffer in C++? A) clear() B) cin.ignore() C) flush() D) cin.clear() Explanation: cin.ignore() is used to clear the input buffer.

Which of the following is the correct way to read a string in C++? A) cin >> "string"; B) cin << "string"; C) cin >> string; D) input >> string; Explanation: cin >> is used to read a string or word, but spaces will be ignored.

The setw() function in C++ is used to: A) Set the width of the output B) Set the value of a variable C) Display a value with a specific number of decimal places D) Set the size of an array Explanation: setw() sets the width for the next input/output operation.

What does the flush function do in the context of output? A) Delays output B) Clears the output buffer C) Terminates the program D) Moves to the next line Explanation: flush is used to clear the output buffer, forcing immediate display.

Which of the following outputs the number 10 with width 5? A) cout << setw(10) << 10; B) cout << 10 << setw(5); C) cout << setw(5) << 10; D) cout << 10 << 5; Explanation: setw(5) ensures the number is displayed with a total width of 5 characters.

Which of the following is used to handle input errors in C++? A) cin.fail() B) error() C) cin.clear() D) cin.ignore() Explanation: cin.clear() clears the error state flag on cin after an input error.

Which function can be used to ignore characters in the input stream? A) cin.clear() B) cin.ignore() C) cin.ignore(); D) cin.stop() Explanation: cin.ignore() is used to skip characters in the input stream.

How do you insert multiple spaces in the output in C++? A) cout << "\t"; B) cout << " "; C) cout << "\n"; D) cout << "/t"; Explanation: You can insert spaces by adding the space character " " in the output.

Which of the following outputs a string in uppercase? A) cout << "HELLO"; B) cout << "hello".upper(); C) cout << setw("hello"); D) cout << "hello"; Explanation: You can manually convert a string to uppercase by manipulating the characters.

Which operator is used to concatenate strings in C++? A) + B) & C) = D) . Explanation: The + operator is used to concatenate strings in C++.

How do you print a string on the next line? A) cout << "\t"; B) cout << endl; C) cout << " "; D) cout << "\n"; Explanation: endl inserts a newline and flushes the buffer.

Which of these is used for formatted output in C++? A) printf() B) write() C) cout with manipulators D) show() Explanation: cout with manipulators like setw(), setprecision(), etc., is used for formatted output.

Which of the following is a C++ operator for formatted output? A) % B) << C) @ D) // Explanation: << is used with cout to perform formatted output in C++.

What does the setprecision() function do in C++? A) Sets the font size B) Sets the number of decimal places for floating-point numbers C) Sets the color of the output D) Sets the width of the output Explanation: setprecision() controls the number of digits displayed after the decimal point.

Which function is used to clear the output buffer? A) clear() B) reset() C) flush() D) buffer() Explanation: The flush() function is used to clear the output buffer.

Which statement is used to handle an error in input operation? A) cin.error() B) cin.fail() C) error() D) cin.clear() Explanation: cin.fail() checks if the previous input operation failed.

What happens when the cin >> x; operation fails? A) The program continues normally B) The variable x gets the default value C) The failbit is set D) The program terminates Explanation: When an error occurs during input, the failbit is set to indicate failure.

What is the default state of the failbit in C++? A) Set B) Clear C) Ignored D) Frozen Explanation: The failbit is cleared by default when input operations are successful.

Which of the following clears the error state of cin? A) cin.stop() B) cin.clear() C) cin.ignore() D) reset() Explanation: cin.clear() clears any error flags (like failbit) from cin.

How would you print a floating-point number with 2 decimal places in C++? A) cout << fixed << setprecision(2) << x; B) cout << x << 2; C) cout << fixed << setprecision(2) << x; D) cout << "fixed(x)"; Explanation: setprecision(2) ensures the floating-point number is printed with 2 decimal places.

The endl manipulator is used to: A) Flush the output buffer B) Set precision C) Add a new line D) Insert tabs Explanation: endl adds a new line and flushes the output buffer.

Chapter 4: Control Structures

Control structures are used to: A) Store data B) Control the flow of program execution C) Display output D) Define variables Explanation: Control structures manage the logical flow of instructions based on conditions or loops.
How many types of basic control structures are there in C++? A) 2 B) 3 C) 4 D) 5 Explanation: There are three basic control structures: sequence, selection, and repetition.
The default control structure in any program is: A) Selection B) Loop C) Sequence D) Function Explanation: Sequence is the default structure where instructions are executed in order.
The if statement is a type of: A) Loop B) Sequence C) Selection D) Repetition Explanation: if is a selection structure used for decision-making.
Which control structure is used to repeat a block of code? A) if B) switch C) loop D) return Explanation: Looping structures like while, for, and do-while repeat code blocks.
In C++, which keyword is used for multiple decision control? A) if B) for C) switch D) goto Explanation: switch is used for multi-way branching based on variable values.
What is the syntax of an if statement? A) if (condition); B) if condition {} C) if (condition) { // code } D) if = condition Explanation: The correct syntax uses parentheses around the condition and curly braces for the block.
The else statement is executed when: A) The condition is true B) The condition is false C) The loop ends D) A variable is zero Explanation: else runs when the if condition is not satisfied.
The else if ladder is used when: A) Only one condition is checked B) Multiple conditions are checked C) Loop is repeated D) Input is taken Explanation: else if helps check multiple exclusive conditions in a sequence.
A switch statement uses: A) Boolean conditions B) Constant expressions C) Loops D) Input functions Explanation: Each case in a switch must use constant expressions.
A case block in a switch ends with: A) break B) break; C) exit D) stop Explanation: The break; prevents fall-through in the switch structure.
If break is omitted in a switch case: A) The program halts B) Error is shown C) Control flows to the next case D) Case is skipped Explanation: Without break, control moves into the next case block.
A loop that executes at least once is: A) while B) do-while C) for D) goto Explanation: do-while executes the loop body before checking the condition.
In a for loop, the initialization is done: A) At the end B) At the beginning C) Inside the body D) Outside the loop Explanation: Initialization is done before the first iteration.
Which loop checks the condition before executing the block? A) do-while B) while C) goto D) continue Explanation: while checks the condition first; if false, the block isn't executed.
The syntax of a for loop is: A) for i = 0; i < n; ++i B) for (i < n; i++; i = 0) C) for (int i = 0; i < n; i++) D) for int i < n Explanation: Proper syntax includes all three parts: initialization; condition; increment.
What will continue do in a loop? A) Exit the loop B) Skip current iteration C) Stop program D) Reset loop Explanation: continue skips the current iteration and goes to the next.
The break statement in a loop: A) Immediately exits the loop B) Skips to the next iteration C) Repeats the loop D) Displays output Explanation: break stops loop execution and exits immediately.
A loop that never ends is called: A) complete loop B) infinite loop C) partial loop D) final loop Explanation: If the condition never becomes false, the loop runs infinitely.
Which keyword transfers control out of a loop? A) skip B) break C) pass D) exit Explanation: break is used to exit from a loop prematurely.
In a while loop, the loop runs: A) Until a break is found B) As long as the condition is true C) One time only D) Even if condition is false Explanation: A while loop continues as long as the condition remains true.
What happens if the condition in a while loop is false initially? A) The loop runs once B) The loop doesn't run at all C) Error occurs D) Skips one step Explanation: The condition is checked first; if false, the loop body is skipped.
The keyword goto is used for: A) Repeating blocks B) Jumping to a labeled statement C) Input handling D) Loop increment Explanation: goto causes the program to jump to a specified label.
The default label in switch is executed when: A) No cases match B) All cases match C) First case matches D) Last case matches Explanation: If none of the cases match, the default block is executed.
Which loop is most suitable when the number of iterations is known? A) while B) for C) do-while D) if Explanation: A for loop is best when the number of repetitions is known beforehand.
Nested control structures mean: A) Functions inside functions B) Control structures inside others C) Variables within loops D) Header files Explanation: A nested structure places one control structure inside another (e.g., a loop inside an if).
if (x == 10) checks if: A) x equals 0 B) x equals 10 C) x is more than 10 D) x is not 10 Explanation: == is the comparison operator that checks equality.
What type of value does a condition return? A) Integer B) Float C) Boolean D) String Explanation: Conditions return a boolean value — either true or false.
Which control structure ensures at least one execution? A) while B) for C) do-while D) if-else Explanation: do-while runs the block once before checking the condition.
Control structures help to: A) Declare variables B) Manage program logic and decisions C) Create new files D) Compile programs Explanation: They are used to control logic flow, decisions, and iterations in code.

Chapter 5: Functions

A function is a: A) Variable B) Data type C) Block of code that performs a task D) Constant Explanation: A function is a named block of code designed to perform a specific task.
Which keyword is used to define a function in C++? A) define B) method C) void/int/float/etc. D) def Explanation: In C++, functions are defined using return types like void, int, etc., followed by the function name.
The function from where execution of a program begins is: A) start() B) run() C) main() D) execute() Explanation: The main() function is the entry point of every C++ program.
A function that does not return a value is declared as: A) int B) void C) char D) null Explanation: void indicates the function does not return any value.
A function can return how many values at a time? A) 2 B) 1 C) Unlimited D) None Explanation: A C++ function can return only one value using the return statement.
Which of the following is NOT a part of a function definition? A) Function name B) Return type C) Compiler version D) Parameter list Explanation: The compiler version is unrelated to function structure.
What are the inputs passed to a function called? A) Returns B) Parameters/Arguments C) Constants D) Blocks Explanation: Inputs passed to functions are called parameters or arguments.
The variables defined inside a function are called: A) Global variables B) Constants C) Local variables D) Reference variables Explanation: Variables inside a function are local and accessible only within that function.
The variables defined outside all functions are called: A) Block variables B) Global variables C) Loop variables D) Constants Explanation: Global variables are declared outside all functions and are accessible anywhere in the program.
A function with the same name but different parameters is an example of: A) Recursion B) Inheritance C) Function overloading D) Polymorphism Explanation: Function overloading allows multiple functions with the same name but different parameter lists.
Which keyword is used to return a value from a function? A) give B) send C) return D) stop Explanation: The return keyword is used to send a value back to the calling function.
A function that calls itself is known as: A) Loop function B) Recursive function C) Overloaded function D) Main function Explanation: Recursive functions are those that call themselves directly or indirectly.
What is the purpose of a function prototype? A) To define logic B) To declare a function before main() C) To compile program D) To debug code Explanation: A function prototype tells the compiler about the function name, return type, and parameters before its definition.
Function prototypes end with: A) colon B) comma C) semicolon D) bracket Explanation: Like most declarations, prototypes end with a semicolon (;).
How many times can a function be called? A) Once B) Twice C) As many times as needed D) Only in main() Explanation: Functions can be called multiple times from anywhere they are in scope.
What is the correct syntax for calling a function named sum()? A) call sum; B) run sum; C) sum(); D) return sum(); Explanation: Functions are called by writing their name followed by parentheses, e.g., sum();.
What happens if a function is called but not defined? A) It runs by default B) Program works C) Compiler error occurs D) It skips Explanation: If a called function isn't defined, the compiler throws an error.
A function that returns an integer must be declared as: A) float B) void C) int D) string Explanation: To return integers, the return type must be int.
What type of values can functions return? A) Only int B) Only float C) Any data type D) Only string Explanation: Functions can return values of any valid data type (int, float, char, etc.).
In C++, the main() function returns a value of type: A) void B) int C) char D) float Explanation: By default, main() returns int in standard C++.
Which of the following is true about local variables? A) They are accessible globally B) They are declared outside functions C) They are destroyed after function ends D) They are permanent Explanation: Local variables exist only during the function's execution.
What happens if a function has no return statement but is declared as int? A) It returns zero B) Compilation error may occur C) It works normally D) It gives output Explanation: If an int function doesn’t return a value, it can lead to warnings or undefined behavior.
A function that returns nothing is declared with: A) null B) none C) void D) int Explanation: The keyword void specifies no value is returned.
Which of these is used to define a function body? A) Parentheses B) Square brackets C) Curly braces D) Colon Explanation: The body of a function is enclosed in curly braces { }.
A function can have: A) No parameter B) One parameter C) Multiple parameters D) All of the above Explanation: Functions can have no, one, or many parameters.
Which of the following is NOT a valid function name? A) display B) sum2 C) 2sum D) average_result Explanation: Function names cannot begin with a digit.
Which part of the function defines what it does? A) Declaration B) Call C) Definition D) Prototype Explanation: The function definition includes the actual body — what the function does.
Which keyword is used to exit a function early? A) break B) exit C) return D) stop Explanation: return exits the function and optionally passes a value back.
Why are functions used in programs? A) To increase memory usage B) To slow down the code C) To reuse code and make it manageable D) To replace loops Explanation: Functions improve modularity and reusability in programs.
A function header includes: A) Only return type B) Return type, function name, parameter list C) Only function body D) Only variable declarations Explanation: The header specifies return type, function name, and its parameters (if any).

Chapter 6: Digital Logic and Design

Digital systems work with: A) Continuous signals B) Electric waves C) Discrete signals (0s and 1s) D) Magnetic pulses Explanation: Digital systems process binary data, which consists of discrete 0 and 1 signals.
Binary number system uses how many digits? A) 3 B) 10 C) 2 D) 8 Explanation: The binary system only uses two digits: 0 and 1.
The base of the binary number system is: A) 10 B) 8 C) 2 D) 16 Explanation: Binary is base-2, meaning it uses only two symbols (0 and 1).
1 + 1 in binary equals: A) 1 B) 10 C) 10 (binary for 2) D) 11 Explanation: 1 + 1 = 10 in binary (which equals 2 in decimal).
Which logic gate gives HIGH output only when all inputs are HIGH? A) OR B) NOT C) AND D) XOR Explanation: The AND gate outputs 1 only if all inputs are 1.
Which logic gate gives HIGH output if at least one input is HIGH? A) OR B) AND C) NAND D) NOR Explanation: The OR gate gives 1 if any input is 1.
The NOT gate is also called: A) Buffer B) Flip-Flop C) Inverter D) Controller Explanation: The NOT gate inverts the input: 1 becomes 0, and 0 becomes 1.
The output of a NOT gate when input is 1 is: A) 1 B) 0 C) 10 D) Undefined Explanation: NOT gate inverts 1 to 0.
The basic logic gates are: A) NAND, NOR, XOR B) AND, OR, NOT C) NOT, XOR, XNOR D) NOR, AND, NAND Explanation: The three basic gates are AND, OR, and NOT.
Which gate is known as the universal gate? A) XOR B) OR C) NAND D) NOT Explanation: NAND is a universal gate because it can be used to create any other logic gate.
The output of an AND gate with inputs 1 and 0 is: A) 1 B) 0 C) 0 D) 10 Explanation: AND gate only gives 1 if both inputs are 1.
The output of an OR gate with inputs 0 and 0 is: A) 1 B) 0 C) 10 D) Undefined Explanation: OR gate gives 1 if at least one input is 1. If both are 0, output is 0.
What is the binary equivalent of decimal 5? A) 1010 B) 1001 C) 101 D) 110 Explanation: 5 in decimal equals 101 in binary.
The decimal of binary 1101 is: A) 13 B) 11 C) 13 D) 14 Explanation: 1101 in binary equals 13 in decimal.
Which number system uses digits 0 to 9 and A to F? A) Binary B) Octal C) Hexadecimal D) Decimal Explanation: Hexadecimal uses base-16 with digits 0-9 and letters A-F.
The full form of ASCII is: A) Advanced System for Coding Information B) Algorithmic Scheme for Code Input C) American Standard Code for Information Interchange D) Automated Software Code Instruction Explanation: ASCII is a coding standard for representing characters as numbers.
What is 1 + 1 + 1 in binary? A) 10 B) 11 C) 11 (binary for 3) D) 100 Explanation: 1 + 1 + 1 = 11 in binary.
Which gate outputs LOW only when all inputs are HIGH? A) AND B) OR C) NAND D) XOR Explanation: NAND gate is the inverse of AND: it gives 0 only when all inputs are 1.
A truth table shows: A) Diagrams B) Input-output relationships of logic gates C) Graphs D) Circuits Explanation: Truth tables list all possible inputs and corresponding outputs of logic gates.
Which of the following is not a binary number? A) 1011 B) 1201 C) 0101 D) 1000 Explanation: Binary numbers only include 0s and 1s; 1201 includes a 2.
Which of the following converts decimal to binary? A) OR gate B) Binary conversion method C) NAND gate D) Multiplier Explanation: Binary conversion uses division by 2 to convert decimal numbers.
What is the output of NOT (0)? A) 0 B) 1 C) 10 D) Undefined Explanation: NOT inverts 0 to 1.
The logic gate used to compare two binary digits is: A) NAND B) OR C) XOR D) NOT Explanation: XOR gives 1 only when inputs are different — useful for comparison.
In binary, what is 1111 + 0001? A) 1110 B) 1111 C) 10000 D) 11000 Explanation: 1111 (15) + 0001 (1) = 10000 (16) in binary.
Digital circuits are made of: A) Microcontrollers B) Logic gates C) Memory units D) Floppy disks Explanation: Logic gates are the building blocks of digital circuits.
A half adder is used for: A) Division B) Addition of two bits C) Subtraction D) Comparison Explanation: A half adder adds two single-bit binary numbers.
The output of XOR gate is true if: A) Both inputs are 1 B) Inputs are different C) Inputs are same D) Input is 0 Explanation: XOR outputs 1 only when the two inputs differ.
How many possible input combinations exist for a 2-input gate? A) 2 B) 3 C) 4 D) 5 Explanation: 2 inputs → 2² = 4 combinations: 00, 01, 10, 11.
Logic gates are implemented using: A) Software B) Sensors C) Electronic circuits D) Switches only Explanation: Gates are built using electronic circuits like transistors.
Which logic gate provides the opposite output of OR? A) XOR B) NAND C) NOR D) AND Explanation: NOR is the inverse of OR — it gives 1 only when all inputs are 0. Here are 30 MCQs from Chapter 7: Introduction to Scratch (Computer Science 10th Class STBB, English Medium), with bolded correct answers and clear explanations, formatted cleanly without lines between questions:

Chapter 7: Introduction to Scratch

Scratch is a: A) Text-based language B) Block-based visual programming language C) Markup language D) Hardware tool Explanation: Scratch uses blocks to build programs visually, ideal for beginners and students.
Scratch was developed by: A) Microsoft B) MIT Media Lab C) Apple D) Google Explanation: Scratch was developed by the MIT Media Lab to make programming accessible to children.
In Scratch, the character that performs actions is called a: A) Object B) Player C) Sprite D) Icon Explanation: A sprite is the main character or object that carries out tasks in a Scratch program.
The area where sprites move is called the: A) Command line B) Stage C) Platform D) Terminal Explanation: The stage is the visual area where all sprite actions are displayed.
Scratch scripts are made using: A) Syntax rules B) Text commands C) Blocks D) Codes Explanation: Scratch scripts are formed by snapping together colored blocks that represent commands.
Each block in Scratch is a: A) Program B) Command line C) Instruction or action D) File Explanation: Every block represents a specific instruction for the sprite.
Scratch projects are saved with the extension: A) .exe B) .scr C) .sb or .sb3 D) .scratch Explanation: Scratch files are saved as .sb, .sb2, or .sb3 depending on the version.
The green flag in Scratch is used to: A) Stop the program B) Save the script C) Start the program D) Open a new project Explanation: Clicking the green flag starts the script from the beginning.
The red stop button is used to: A) Run code B) Stop all running scripts C) Clear the stage D) Refresh sprite Explanation: The red stop button halts all ongoing actions in Scratch.
The command to repeat a set of instructions is: A) move B) turn C) repeat D) say Explanation: The repeat block is used for loops, repeating instructions a set number of times.
Motion blocks are used to: A) Paint sprites B) Move sprites C) Add sound D) Delete code Explanation: Motion blocks control the movement of sprites on the stage.
The Looks block category is used for: A) Jumping B) Changing sprite appearance or speaking C) Making sound D) Timing Explanation: Looks blocks handle sprite appearances, speech, and visual effects.
The Sound block is used to: A) Move sprite B) Add or play sounds C) Create background D) Speak text Explanation: The Sound block category lets users add and control audio playback.
The Pen block is used for: A) Changing sprite B) Drawing on the stage C) Typing text D) Zooming in Explanation: Pen blocks allow sprites to draw lines and shapes on the stage.
Control blocks manage: A) Size B) Loops and conditions C) Color D) Costumes Explanation: Control blocks manage the flow of scripts, like repetition and decisions.
Which block is used to make a decision? A) move B) repeat C) if D) glide Explanation: The if block allows conditional execution of code.
A variable in Scratch is created to: A) Change color B) Store data C) Draw shapes D) Move sprite Explanation: Variables in Scratch are used to store and change values during script execution.
The command to wait for a specified time is: A) delay B) wait C) hold D) freeze Explanation: The wait block pauses the script for a specific duration.
Scratch supports: A) Only sound B) Animation, sound, and logic C) Text only D) Hardware control only Explanation: Scratch combines sound, motion, control, and logic in an interactive way.
The backdrop in Scratch is: A) A sprite B) A sound C) Background of the stage D) Costume Explanation: The backdrop is the background scenery displayed behind the sprites.
What is a script in Scratch? A) A variable B) A sprite C) A group of connected blocks D) A costume Explanation: A script is a stack of blocks snapped together to control sprite behavior.
What is the purpose of the forever block? A) Stop a script B) Repeat actions continuously C) Store variables D) Clone a sprite Explanation: The forever block repeats the contained actions endlessly.
In Scratch, a costume refers to: A) A background B) A voice C) Appearance of a sprite D) A drawing Explanation: Costumes define how a sprite looks; a sprite can switch between multiple costumes.
The sensing block is used to: A) Move sprites B) Detect conditions and interactions C) Control timing D) Make decisions Explanation: Sensing blocks detect interactions, such as touching another sprite or key presses.
What does the "say" block do? A) Play music B) Makes the sprite display a speech bubble C) Changes sound D) Sends a message Explanation: The say block makes the sprite show a message in a speech bubble.
Broadcasting in Scratch is used for: A) Sound control B) Loop creation C) Sending messages between sprites D) Drawing shapes Explanation: broadcast sends a message that other sprites can respond to.
Which block waits until a message is received before executing? A) say B) forever C) when I receive D) control Explanation: when I receive listens for a broadcast message to begin its script.
Which Scratch block can control time-based actions? A) repeat B) if C) wait D) glide Explanation: The wait block is used to delay actions by seconds.
What kind of programming model does Scratch use? A) Functional B) Event-driven C) Object-oriented D) Procedural Explanation: Scratch runs scripts in response to events like clicking the green flag or pressing a key.
In Scratch, events begin with: A) say block B) repeat block C) hat blocks like “when green flag clicked” D) costume changes Explanation: Hat blocks (top of a stack) start scripts in response to events.

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