Pariksha SaathiGeneral Studies
General Science: Practice Questions with Answers
480 practice questions on General Science, with answers; most also have an explanation or a worked solution. Try each one before you open its answer.
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Q.351
The pale yellow colour of normal urine is due to the pigment
- A Melanin
- B Urochrome
- C Carotene
- D Haemoglobin
Show answer
Correct answer: (B) Urochrome
Urochrome, a pigment formed from the breakdown of haemoglobin, gives urine its yellow colour. Melanin is the pigment of skin and hair, and carotene is the orange-yellow pigment of carrots.
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Q.352
A light-year is a unit of
- A distance
- B time
- C speed of light
- D intensity of light
Show answer
Correct answer: (A) distance
A light-year is the distance travelled by light in vacuum in one year, about 9.46 × 10¹⁵ m. It is used to express astronomical distances, not time.
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Q.353
One astronomical unit (AU) is equal to the
- A distance travelled by light in one year
- B mean distance between the Earth and the Sun
- C mean distance between the Earth and the Moon
- D radius of the Earth
Show answer
Correct answer: (B) mean distance between the Earth and the Sun
1 AU is the mean distance between the Earth and the Sun, about 1.5 × 10¹¹ m. The distance light travels in one year is a light-year.
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Q.354
Which blood vessel carries deoxygenated blood from the heart to the lungs?
- A Pulmonary artery
- B Pulmonary vein
- C Aorta
- D Vena cava
Show answer
Correct answer: (A) Pulmonary artery
The right ventricle pumps deoxygenated blood into the pulmonary artery, which takes it to the lungs; it is an exception to the rule that arteries carry oxygenated blood. The pulmonary veins bring oxygenated blood from the lungs back to the heart.
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Q.355
A bar magnet is pushed into a coil connected to a galvanometer, and the needle deflects. If the magnet is now held stationary inside the coil, the galvanometer shows
- A a larger deflection in the same direction
- B a steady deflection in the opposite direction
- C no deflection
- D a deflection that keeps increasing
Show answer
Correct answer: (C) no deflection
A current is induced only while the magnetic field linked with the coil is changing. When the magnet is at rest relative to the coil there is no change, so no current is induced and the needle returns to zero.
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Q.356
Which group of plants is called the 'amphibians of the plant kingdom'?
- A Bryophyta
- B Thallophyta
- C Pteridophyta
- D Gymnosperms
Show answer
Correct answer: (A) Bryophyta
Bryophytes such as mosses (Funaria) and Marchantia live on land but need water for fertilisation, so they are called the amphibians of the plant kingdom. Thallophytes (algae) are mainly aquatic.
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Q.357
The enzyme lipase breaks down fats into
- A Amino acids
- B Fatty acids and glycerol
- C Glucose
- D Peptones
Show answer
Correct answer: (B) Fatty acids and glycerol
Lipase, present in pancreatic and intestinal juice, digests emulsified fats into fatty acids and glycerol, which are then absorbed. Proteins are digested into amino acids and carbohydrates into glucose.
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Q.358
In the electrolysis of water, which of the following is correct?
- A Oxygen collects at the cathode and hydrogen at the anode, in the volume ratio 2 : 1
- B Hydrogen collects at the cathode and oxygen at the anode, in the volume ratio 1 : 2
- C Hydrogen and oxygen collect in equal volumes
- D Hydrogen collects at the cathode and oxygen at the anode, in the volume ratio 2 : 1
Show answer
Correct answer: (D) Hydrogen collects at the cathode and oxygen at the anode, in the volume ratio 2 : 1
By the equation 2H₂O → 2H₂ + O₂, electrolysis gives twice as much hydrogen as oxygen by volume. Hydrogen is released at the cathode (negative electrode) and oxygen at the anode (positive electrode).
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Q.359
The speed of sound in air increases with
- A a decrease in temperature
- B an increase in temperature
- C a decrease in humidity
- D a decrease in the frequency of the sound
Show answer
Correct answer: (B) an increase in temperature
The speed of sound in a medium increases as its temperature rises; humid air also carries sound slightly faster than dry air. The speed of sound in a given medium does not depend on its frequency.
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Q.360
A block slides on a rough horizontal floor and slows down. The work done by the force of friction on the block is
- A positive, because friction acts along the motion
- B zero, because friction does not move the block
- C negative, because friction acts opposite to the displacement
- D zero, because the floor is horizontal
Show answer
Correct answer: (C) negative, because friction acts opposite to the displacement
Friction acts opposite to the direction of displacement, so the work done by it is negative. It takes kinetic energy away from the block, which is why the block slows down.
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Q.361
Elements placed in the same group of the modern periodic table have the same
- A Number of valence electrons
- B Number of shells
- C Atomic mass
- D Number of neutrons
Show answer
Correct answer: (A) Number of valence electrons
All elements of a group have the same number of valence electrons, which is why they show similar chemical properties. Elements in the same period, on the other hand, have the same number of shells.
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Q.362
Which of the following statements about evaporation is correct?
- A It takes place only at the boiling point of the liquid
- B It takes place throughout the whole mass of the liquid
- C It takes place from the surface of the liquid at temperatures below its boiling point
- D Its rate decreases when the surface area is increased
Show answer
Correct answer: (C) It takes place from the surface of the liquid at temperatures below its boiling point
Evaporation is a surface phenomenon that occurs at any temperature below the boiling point. Boiling is the bulk process that happens at the boiling point, and a larger surface area increases the rate of evaporation.
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Q.363
An element has the electronic configuration 2, 8, 2. Its position in the modern periodic table is
- A Group 2, Period 2
- B Group 3, Period 2
- C Group 12, Period 3
- D Group 2, Period 3
Show answer
Correct answer: (D) Group 2, Period 3
Its electrons occupy three shells, so it is in Period 3, and its 2 valence electrons place it in Group 2. The element is magnesium (atomic number 12).
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Q.364
When 3 kg of a fuel is burnt completely, 150,000 kJ of heat is produced. What is the calorific value of the fuel?
- A 450,000 kJ/kg
- B 50,000 kJ/kg
- C 150,000 kJ/kg
- D 5,000 kJ/kg
Show answer
Correct answer: (B) 50,000 kJ/kg
Calorific value is the heat produced by the complete combustion of 1 kg of a fuel. So it is 150,000 kJ ÷ 3 kg = 50,000 kJ/kg.
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Q.365
The mass of one of two bodies is doubled and the distance between them is also doubled. The gravitational force between them becomes
- A twice the original
- B half the original
- C the same as before
- D one-fourth of the original
Show answer
Correct answer: (B) half the original
F ∝ m₁m₂/r². Doubling one mass multiplies F by 2, and doubling r divides it by 4, so the new force = 2/4 = ½ of the original.
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Q.366
The roots of a plant grow downwards into the soil, in the direction of gravity. This response is called
- A Negative geotropism
- B Positive phototropism
- C Positive geotropism
- D Negative phototropism
Show answer
Correct answer: (C) Positive geotropism
Roots grow towards the pull of gravity, which is positive geotropism. Shoots grow away from gravity (negative geotropism) and towards light (positive phototropism).
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Q.367
What happens to the diaphragm and the chest cavity when we breathe in?
- A The diaphragm becomes dome-shaped and the chest cavity becomes smaller
- B The diaphragm flattens and the chest cavity becomes smaller
- C The diaphragm becomes dome-shaped and the chest cavity becomes larger
- D The diaphragm flattens and the chest cavity becomes larger
Show answer
Correct answer: (D) The diaphragm flattens and the chest cavity becomes larger
During inhalation the diaphragm contracts and flattens and the ribs are lifted, so the chest cavity becomes larger and air is drawn into the lungs. During exhalation the diaphragm relaxes back into its dome shape and the cavity becomes smaller.
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Q.368
How many base (fundamental) quantities are there in the SI system of units?
- A 5
- B 6
- C 9
- D 7
Show answer
Correct answer: (D) 7
The SI has seven base quantities: length, mass, time, electric current, thermodynamic temperature, amount of substance and luminous intensity. All other quantities are derived from these.
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Q.369
The antibiotic penicillin was discovered by
- A Louis Pasteur
- B Robert Koch
- C Alexander Fleming
- D Edward Jenner
Show answer
Correct answer: (C) Alexander Fleming
Alexander Fleming noticed that a Penicillium mould stopped the growth of bacteria, which led to the discovery of penicillin. Pasteur is known for pasteurisation and Jenner for the smallpox vaccine.
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Q.370
Which of the following statements about magnetic field lines is correct?
- A No two magnetic field lines ever intersect each other
- B Outside a magnet, they emerge from the south pole and enter the north pole
- C They are farthest apart where the magnetic field is strongest
- D They are open curves that begin and end in empty space
Show answer
Correct answer: (A) No two magnetic field lines ever intersect each other
If two field lines crossed, a compass needle at that point would point in two directions at once, which is impossible. Outside a magnet the lines go from the north pole to the south pole, they are crowded where the field is strong, and they form closed curves.
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Q.371
Hydraulic brakes and hydraulic lifts work on the principle of
- A Archimedes' principle
- B Bernoulli's principle
- C Pascal's law
- D Newton's third law
Show answer
Correct answer: (C) Pascal's law
Pascal's law states that pressure applied to an enclosed liquid is transmitted equally in all directions, so a small force at the pedal produces a large force at the brake shoes. Archimedes' principle explains floating and buoyancy.
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Q.372
In the garden pea plants studied by Mendel, which of the following traits is recessive?
- A Round seed
- B Yellow seed
- C Tall stem
- D Green seed
Show answer
Correct answer: (D) Green seed
In pea, yellow seed colour is dominant over green, round seed shape over wrinkled, and tall stem over dwarf. So green seed colour is the recessive trait here; it shows only when both copies of the gene are for green.
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Q.373
Which of the following is an endothermic reaction?
- A Burning of natural gas
- B Respiration
- C Decomposition of vegetable matter into compost
- D Decomposition of calcium carbonate on heating
Show answer
Correct answer: (D) Decomposition of calcium carbonate on heating
Calcium carbonate breaks down into calcium oxide and carbon dioxide only while heat is supplied, so this reaction absorbs heat. Burning of natural gas, respiration and the decomposition of vegetable matter into compost all release heat (exothermic).
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Q.374
Cardiac muscles, found in the heart, are
- A Striated and involuntary
- B Striated and voluntary
- C Unstriated and voluntary
- D Unstriated and involuntary
Show answer
Correct answer: (A) Striated and involuntary
Cardiac muscle cells are cylindrical, branched, uninucleate and striated, and they contract rhythmically throughout life without our control, so they are involuntary. Skeletal muscles are striated and voluntary; smooth muscles are unstriated and involuntary.
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Q.375
A doctor's stethoscope carries the sound of a patient's heartbeat to the doctor's ears by
- A Refraction of sound
- B Multiple reflection of sound
- C Absorption of sound
- D Diffraction of sound
Show answer
Correct answer: (B) Multiple reflection of sound
In a stethoscope the sound of the heartbeat travels along the tube by repeated (multiple) reflections and reaches the doctor's ears. Megaphones and soundboards also make use of the reflection of sound.
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Q.376
Optical fibres used in communication and endoscopy work on the principle of
- A Refraction
- B Dispersion
- C Total internal reflection
- D Scattering
Show answer
Correct answer: (C) Total internal reflection
Light entering the fibre strikes its wall at angles greater than the critical angle and is totally internally reflected, travelling along the fibre with very little loss. Mirage and the sparkle of a diamond are other examples of total internal reflection.
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Q.377
The ozone layer in the upper atmosphere protects life on Earth from the Sun's harmful
- A Ultraviolet radiation
- B Infrared radiation
- C Radio waves
- D Visible light
Show answer
Correct answer: (A) Ultraviolet radiation
The ozone layer absorbs most of the harmful ultraviolet (UV) radiation from the Sun, which can cause skin cancer and damage living cells.
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Q.378
Which of the following medical techniques uses ultrasound?
- A Electrocardiography (ECG)
- B X-ray radiography
- C CT scan
- D Echocardiography
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Correct answer: (D) Echocardiography
Echocardiography forms an image of the heart from reflected ultrasonic waves. An ECG records the heart's electrical activity, while X-ray radiography and CT scans use X-rays.
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Q.379
A ray of light falls on a plane mirror making an angle of 40° with the surface of the mirror. The angle of reflection is
- A 40°
- B 50°
- C 80°
- D 90°
Show answer
Correct answer: (B) 50°
Angles are measured from the normal, so the angle of incidence is 90° - 40° = 50°. By the law of reflection, the angle of reflection equals the angle of incidence, i.e. 50°.
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Q.380
3 g of carbon combines with 8 g of oxygen to form 11 g of carbon dioxide. If 3 g of carbon is burnt in 50 g of oxygen, the mass of carbon dioxide formed will be
- A 53 g
- B 11 g
- C 50 g
- D 42 g
Show answer
Correct answer: (B) 11 g
By the law of constant proportions, 3 g of carbon always combines with only 8 g of oxygen, giving 11 g of CO₂. The remaining 50 - 8 = 42 g of oxygen is left unused.
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Q.381
The largest gland in the human body is the
- A Pancreas
- B Liver
- C Thyroid
- D Salivary gland
Show answer
Correct answer: (B) Liver
The liver, situated in the upper right part of the abdomen, is the largest gland in the body; it secretes bile and stores glycogen. The pancreas, thyroid and salivary glands are much smaller.
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Q.382
Herbivores such as cows have a longer small intestine than carnivores such as tigers because
- A The cellulose in grass needs a longer time to be digested
- B Meat is harder to digest than grass
- C Herbivores do not produce any digestive enzymes
- D Grass contains more fat than meat
Show answer
Correct answer: (A) The cellulose in grass needs a longer time to be digested
Grass is rich in cellulose, which takes a long time to digest, so herbivores need a longer small intestine. Meat is easier to digest, so carnivores like tigers have a shorter small intestine.
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Q.383
Which group of plants has a body differentiated into roots, stem and leaves with vascular tissue, but does not produce seeds?
- A Bryophyta
- B Gymnosperms
- C Pteridophyta
- D Angiosperms
Show answer
Correct answer: (C) Pteridophyta
Pteridophytes such as ferns and Marsilea have roots, stems, leaves and vascular tissue, but they reproduce by spores, not seeds. Bryophytes lack vascular tissue, while gymnosperms and angiosperms bear seeds.
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Q.384
Silicon and germanium, used in making diodes, transistors and solar cells, are
- A Conductors
- B Insulators
- C Superconductors
- D Semiconductors
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Correct answer: (D) Semiconductors
Semiconductors have conductivity between that of conductors and insulators, and it increases with temperature or doping. Pure silicon is the base material of computer chips.
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Q.385
Which of the following is non-biodegradable?
- A Polythene bag
- B Vegetable peels
- C Paper
- D Cotton cloth
Show answer
Correct answer: (A) Polythene bag
Polythene is a plastic that bacteria and other decomposers cannot break down, so it stays in the environment for a very long time. Vegetable peels, paper and cotton are broken down by microbes and are biodegradable.
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Q.386
A doctor counts 18 pulse beats in 15 seconds. What is the person's heart rate per minute?
- A 36
- B 54
- C 90
- D 72
Show answer
Correct answer: (D) 72
One minute is 60 s, which is 4 x 15 s, so the rate is 18 x 4 = 72 beats per minute. Each pulse beat corresponds to one heartbeat, so this is also the heart rate.
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Q.387
The area under the velocity-time graph of a moving body gives its
- A acceleration
- B change in velocity
- C momentum
- D displacement
Show answer
Correct answer: (D) displacement
Area under a v-t graph = velocity × time, which is displacement (equal to the distance for motion in one direction). Acceleration is the slope of the v-t graph, and change in velocity is the area under an acceleration-time graph.
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Q.388
Which of the following shows the levels of classification in the correct ascending order, from the smallest group to the largest?
- A Species, Family, Genus, Order, Class, Phylum, Kingdom
- B Species, Genus, Order, Family, Class, Phylum, Kingdom
- C Species, Genus, Family, Class, Order, Phylum, Kingdom
- D Species, Genus, Family, Order, Class, Phylum, Kingdom
Show answer
Correct answer: (D) Species, Genus, Family, Order, Class, Phylum, Kingdom
Species is the basic unit; related species form a genus, genera form a family, families an order, orders a class, classes a phylum (called a division in plants), and phyla a kingdom.
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Q.389
Water droplets appear on the outer surface of a glass containing ice-cold water. This is because
- A Water vapour in the air condenses on the cold surface
- B Water seeps out through the glass
- C Ice inside the glass sublimes
- D Water evaporates from inside the glass and collects outside
Show answer
Correct answer: (A) Water vapour in the air condenses on the cold surface
Water vapour in the surrounding air loses energy on touching the cold glass and condenses into liquid droplets. Glass is not porous, so water cannot seep through it.
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Q.390
Bacteria and fungi that break down the dead remains of plants and animals into simpler substances are called
- A Producers
- B Herbivores
- C Carnivores
- D Decomposers
Show answer
Correct answer: (D) Decomposers
Decomposers break down the complex organic matter of dead plants and animals into simpler substances that return to the soil and are used again by plants. This keeps nutrients cycling in the ecosystem.
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Q.391
The escape velocity from the surface of the Earth is approximately
- A 9.8 km/s
- B 7.9 km/s
- C 3.0 km/s
- D 11.2 km/s
Show answer
Correct answer: (D) 11.2 km/s
Escape velocity on Earth is about 11.2 km/s. 7.9 km/s is the orbital velocity of a satellite close to the Earth, and 9.8 m/s^2 is the acceleration due to gravity.
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Q.392
A metal wire of resistance R is stretched uniformly so that its length becomes double. Assuming its volume stays the same, its new resistance is
- A R/2
- B 2R
- C R/4
- D 4R
Show answer
Correct answer: (D) 4R
If the length doubles at constant volume, the area of cross-section becomes half. Since R = ρl/A, the new resistance = ρ(2l)/(A/2) = 4ρl/A = 4R.
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Q.393
When the equation Fe + H₂O → Fe₃O₄ + H₂ is balanced, the coefficients of Fe, H₂O, Fe₃O₄ and H₂ are respectively
- A 1, 1, 1, 1
- B 3, 4, 1, 4
- C 3, 4, 1, 2
- D 2, 3, 1, 3
Show answer
Correct answer: (B) 3, 4, 1, 4
3Fe + 4H₂O → Fe₃O₄ + 4H₂. Check: there are 3 Fe atoms, 4 O atoms and 8 H atoms on each side.
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Q.394
The five-kingdom classification of living organisms (Monera, Protista, Fungi, Plantae, Animalia) was proposed by
- A R.H. Whittaker
- B Carl Linnaeus
- C Ernst Haeckel
- D Charles Darwin
Show answer
Correct answer: (A) R.H. Whittaker
Whittaker proposed the five kingdoms in 1969 on the basis of cell structure, body organisation and mode of nutrition. Linnaeus gave the two-kingdom system and binomial nomenclature.
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Q.395
Which of the following groups of organisms forms a food chain?
- A Grass, wheat and mango
- B Goat, cow and elephant
- C Grass, fish and goat
- D Grass, goat and human
Show answer
Correct answer: (D) Grass, goat and human
Grass (producer) is eaten by a goat (herbivore), which can in turn be eaten by humans, so grass → goat → human is a food chain. In the other groups the organisms do not feed on one another in sequence; for example, wheat and mango are both producers.
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Q.396
In vermicomposting, kitchen and garden waste is turned into compost with the help of
- A Termites
- B Houseflies
- C Red worms (a type of earthworm)
- D Ants
Show answer
Correct answer: (C) Red worms (a type of earthworm)
In vermicomposting, red worms, a type of earthworm, eat the organic waste and turn it into rich compost. Only biodegradable waste such as vegetable and fruit peels is used, not plastic or glass.
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Q.397
Compressed natural gas (CNG), used as a cleaner fuel in buses and autorickshaws, consists mainly of
- A Butane
- B Propane
- C Hydrogen
- D Methane
Show answer
Correct answer: (D) Methane
Natural gas, and therefore CNG, is mainly methane (CH₄). Butane and propane are the main components of LPG.
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Q.398
Which cell organelle stores, modifies and packages materials made in the cell and is also involved in the formation of lysosomes?
- A Endoplasmic reticulum
- B Nucleolus
- C Golgi apparatus
- D Mitochondria
Show answer
Correct answer: (C) Golgi apparatus
The Golgi apparatus, a system of membrane-bound sacs, stores, modifies and packages products such as proteins from the ER into vesicles and dispatches them; it also forms lysosomes. The ER mainly makes and transports these materials.
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Q.399
Colourless plastids in which materials such as starch, oils and protein granules are stored are called
- A Chloroplasts
- B Chromoplasts
- C Mitochondria
- D Leucoplasts
Show answer
Correct answer: (D) Leucoplasts
Leucoplasts are white (colourless) plastids that store starch, oils and protein granules. Chloroplasts contain chlorophyll for photosynthesis, chromoplasts are coloured plastids, and mitochondria are not plastids at all.
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Q.400
Within a single neuron, a nerve impulse normally travels in which order?
- A Axon → cell body → dendrite
- B Cell body → dendrite → axon
- C Dendrite → axon → cell body
- D Dendrite → cell body → axon
Show answer
Correct answer: (D) Dendrite → cell body → axon
Information is picked up at the tips of the dendrites, the impulse passes to the cell body and then along the axon to its end, from where it is passed to the next neuron.
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How these questions were made
Authored by an AI assistant (Claude) from its own general knowledge of stable, well-established facts (no live lookup) - not reviewed by a subject-matter expert; verify against an official source before relying on any fact.