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.
Read the lesson on this topic →
← Previous Page 7 / 10 Next →
-
Q.301
In a chemical equation, the symbol (aq) written after the formula of a substance means that the substance is
- A A gas
- B A solid precipitate
- C Dissolved in water
- D A pure liquid
Show answer
Correct answer: (C) Dissolved in water
(aq) stands for aqueous, that is, present as a solution in water. The symbols (g), (s) and (l) are used for gases, solids and liquids.
-
Q.302
When we accidentally touch a very hot object, we pull our hand back at once without thinking about it. This reflex action is controlled mainly by the
- A Spinal cord
- B Cerebrum
- C Cerebellum
- D Olfactory lobe
Show answer
Correct answer: (A) Spinal cord
In a reflex arc the sensory nerve carries the signal to the spinal cord, which sends a quick command through a motor nerve to the arm muscles without waiting for the brain to think. The information also reaches the brain, so we become aware of it afterwards.
-
Q.303
Which metal is the most ductile, so that a wire about 2 km long can be drawn from just one gram of it?
- A Iron
- B Aluminium
- C Gold
- D Lead
Show answer
Correct answer: (C) Gold
Gold is the most ductile metal; a wire about 2 km long can be drawn from one gram of it. Iron, aluminium and lead are far less ductile than gold.
-
Q.304
In 1886, E. Goldstein discovered positively charged radiations called canal rays. This discovery led to the identification of the
- A Electron
- B Neutron
- C Nucleus
- D Proton
Show answer
Correct answer: (D) Proton
Canal rays are positively charged; they led to the discovery of the proton, a sub-atomic particle whose charge is equal and opposite to that of the electron and whose mass is about 2000 times greater.
-
Q.305
Calcium oxide (quicklime) reacts vigorously with water to form calcium hydroxide (slaked lime): CaO + H₂O → Ca(OH)₂. This is an example of a
- A Combination reaction
- B Decomposition reaction
- C Displacement reaction
- D Double displacement reaction
Show answer
Correct answer: (A) Combination reaction
Two reactants combine to form a single product, so it is a combination reaction. It also releases a large amount of heat, so it is exothermic.
-
Q.306
Which of the following is an abiotic component of an ecosystem?
- A Temperature
- B Grass
- C Bacteria
- D Deer
Show answer
Correct answer: (A) Temperature
Abiotic components are the non-living physical factors such as temperature, rainfall, wind, soil and minerals. Grass, bacteria and deer are living (biotic) components.
-
Q.307
'Hypo', used in photography as a fixing agent, is chemically
- A Sodium thiosulphate
- B Sodium sulphate
- C Sodium sulphite
- D Silver bromide
Show answer
Correct answer: (A) Sodium thiosulphate
Hypo is sodium thiosulphate (Na₂S₂O₃·5H₂O). In black-and-white photography it dissolves away the unexposed silver bromide from the film; silver bromide itself is the light-sensitive compound.
-
Q.308
Uniform circular motion is called accelerated motion because
- A the speed of the body keeps changing
- B the mass of the body keeps changing
- C the direction of its velocity keeps changing
- D no force acts on the body
Show answer
Correct answer: (C) the direction of its velocity keeps changing
In uniform circular motion the speed is constant but the direction of motion changes at every point, so the velocity changes, and a changing velocity means acceleration. A centripetal force acts towards the centre.
-
Q.309
Oxygen-rich blood coming from the lungs first enters which chamber of the human heart?
- A Left atrium
- B Right atrium
- C Right ventricle
- D Left ventricle
Show answer
Correct answer: (A) Left atrium
Oxygenated blood from the lungs enters the left atrium through the pulmonary veins, passes into the left ventricle and is pumped out to the body. The right atrium receives deoxygenated blood from the body.
-
Q.310
The functional group present in ethanol is
- A Alcohol (–OH)
- B Aldehyde (–CHO)
- C Carboxylic acid (–COOH)
- D Ketone (>C=O)
Show answer
Correct answer: (A) Alcohol (–OH)
Ethanol is an alcohol, and its functional group is the hydroxyl group (–OH). –CHO is the aldehyde group, >C=O the ketone group and –COOH the carboxylic acid group.
-
Q.311
Which tissue, present at the growing tips of stems and roots, increases their length?
- A Apical meristem
- B Lateral meristem
- C Intercalary meristem
- D Sclerenchyma
Show answer
Correct answer: (A) Apical meristem
Apical meristem at the tips of stems and roots increases their length. Lateral meristem (cambium) increases the girth, and intercalary meristem is found near the nodes.
-
Q.312
The handles of cooking pans are often made of wood or plastic because these materials are
- A good conductors of heat
- B good conductors of electricity
- C heavy and strong
- D poor conductors of heat
Show answer
Correct answer: (D) poor conductors of heat
Wood and plastic are poor conductors (insulators) of heat, so heat from the hot pan does not easily reach the hand. The pan itself is made of metal because metals conduct heat well.
-
Q.313
When dilute hydrochloric acid is added to sodium carbonate, the gas evolved turns lime water milky. The milkiness is due to the formation of
- A Calcium hydroxide
- B Calcium carbonate
- C Calcium hydrogen carbonate
- D Calcium oxide
Show answer
Correct answer: (B) Calcium carbonate
The gas is carbon dioxide. It reacts with lime water, Ca(OH)₂, to form insoluble calcium carbonate (CaCO₃) as a white precipitate. If excess CO₂ is passed, soluble calcium hydrogen carbonate forms and the milkiness disappears.
-
Q.314
Goitre, the swelling of the thyroid gland in the neck, is caused by deficiency of
- A Iron
- B Calcium
- C Potassium
- D Iodine
Show answer
Correct answer: (D) Iodine
The thyroid needs iodine to make thyroxine; its lack makes the gland enlarge. Iodised salt is used to prevent goitre. Iron deficiency causes anaemia and calcium deficiency weakens bones and teeth.
-
Q.315
A flute and a violin play a note of the same pitch and loudness, yet we can tell them apart. The characteristic that distinguishes them is
- A Frequency
- B Amplitude
- C Quality (timbre)
- D Speed
Show answer
Correct answer: (C) Quality (timbre)
Quality or timbre depends on the shape of the waveform and lets us distinguish sounds of the same pitch and loudness. Equal pitch means equal frequency, and equal loudness means similar amplitude.
-
Q.316
The modern periodic table has
- A 8 groups and 7 periods
- B 18 groups and 7 periods
- C 7 groups and 18 periods
- D 18 groups and 9 periods
Show answer
Correct answer: (B) 18 groups and 7 periods
The modern (long form) periodic table has 18 vertical columns called groups and 7 horizontal rows called periods. Mendeleev's table had 8 groups.
-
Q.317
The state of matter that consists of super-energetic, super-excited particles in the form of ionised gases, and which is found in stars and fluorescent tubes, is
- A Bose-Einstein condensate
- B Plasma
- C Colloid
- D Vapour
Show answer
Correct answer: (B) Plasma
Plasma is an ionised gas; the Sun and stars glow because of it, and it forms inside fluorescent and neon tubes. A Bose-Einstein condensate, by contrast, forms when a gas of very low density is cooled to super-low temperatures.
-
Q.318
NPK fertilisers supply three major plant nutrients. The letter 'K' stands for
- A Potassium
- B Calcium
- C Sulphur
- D Magnesium
Show answer
Correct answer: (A) Potassium
N, P and K stand for nitrogen, phosphorus and potassium. The symbol K for potassium comes from its Latin name, kalium.
-
Q.319
In the chlor-alkali process, an aqueous solution of sodium chloride (brine) is electrolysed. The products obtained are
- A Sodium metal, chlorine and oxygen
- B Sodium carbonate, chlorine and water
- C Sodium hydroxide, chlorine and hydrogen
- D Hydrochloric acid, sodium and oxygen
Show answer
Correct answer: (C) Sodium hydroxide, chlorine and hydrogen
2NaCl(aq) + 2H₂O(l) → 2NaOH(aq) + Cl₂(g) + H₂(g). Chlorine is released at the anode, hydrogen at the cathode, and sodium hydroxide solution forms near the cathode; the name comes from chlorine and the alkali, NaOH.
-
Q.320
Yeast is added to dough when making bread because, during fermentation, it produces a gas that makes the dough rise. This gas is
- A Carbon dioxide
- B Oxygen
- C Nitrogen
- D Hydrogen
Show answer
Correct answer: (A) Carbon dioxide
During fermentation yeast breaks down sugar into alcohol and carbon dioxide. The bubbles of carbon dioxide make the dough rise and the bread soft and spongy.
-
Q.321
Which of the following statements about heat is correct?
- A Heat and temperature are the same physical quantity
- B Normal human body temperature is 98.6 degrees Celsius
- C Water is used as a coolant in car radiators because it has a high specific heat capacity
- D Heat flows naturally from a colder body to a hotter body
Show answer
Correct answer: (C) Water is used as a coolant in car radiators because it has a high specific heat capacity
Water's specific heat capacity (about 4200 J/kg/K) is among the highest of common substances, so it absorbs a lot of heat with only a small rise in temperature. Normal body temperature is 37 degrees C (98.6 degrees F), and heat flows from hot to cold.
-
Q.322
Which of the following substances changes directly from solid to vapour on heating, without becoming a liquid?
- A Common salt
- B Sugar
- C Camphor
- D Wax
Show answer
Correct answer: (C) Camphor
Camphor sublimes, as do naphthalene, ammonium chloride and iodine. Common salt, sugar and wax first melt into a liquid when heated.
-
Q.323
A person with blood group B has
- A Antigen A on red blood cells and anti-B antibodies in plasma
- B Antigen B on red blood cells and anti-A antibodies in plasma
- C Antigen B on red blood cells and anti-B antibodies in plasma
- D Both antigens A and B on red blood cells and no antibodies in plasma
Show answer
Correct answer: (B) Antigen B on red blood cells and anti-A antibodies in plasma
In the ABO system, a person of group B carries antigen B on the surface of the red blood cells and anti-A antibodies in the plasma. Anti-B together with antigen B would make the person's own blood clump; group AB has both antigens and no antibodies.
-
Q.324
A satellite moves in a circular orbit around the Earth. The work done by the Earth's gravitational force on the satellite is
- A positive
- B negative
- C equal to its kinetic energy
- D zero
Show answer
Correct answer: (D) zero
The gravitational force acts towards the centre of the orbit, perpendicular to the satellite's displacement along the orbit. Since the force is perpendicular to the displacement at every point, the work done is zero.
-
Q.325
The different coloured components (dyes) present in black ink can be separated by
- A Chromatography
- B Sublimation
- C Centrifugation
- D Using a separating funnel
Show answer
Correct answer: (A) Chromatography
In chromatography the dyes rise up the paper with the solvent at different speeds because they differ in solubility, so they separate. The other methods separate sublimable solids, suspended particles and immiscible liquids respectively.
-
Q.326
Plaster of Paris is prepared by heating which of the following substances at 373 K?
- A Gypsum
- B Limestone
- C Bauxite
- D Washing soda
Show answer
Correct answer: (A) Gypsum
On heating at 373 K, gypsum (CaSO₄·2H₂O) loses part of its water of crystallisation and becomes plaster of Paris (calcium sulphate hemihydrate). Limestone is calcium carbonate and bauxite is an ore of aluminium.
-
Q.327
Fluorine, chlorine, bromine and iodine belong to the family of elements called
- A Alkali metals
- B Alkaline earth metals
- C Halogens
- D Noble gases
Show answer
Correct answer: (C) Halogens
Group 17 elements are the halogens (salt-formers), each with 7 valence electrons. Alkali metals are group 1, alkaline earth metals group 2 and noble gases group 18.
-
Q.328
Sulphuric acid, called the 'king of chemicals', is manufactured by the
- A Contact process
- B Ostwald process
- C Haber process
- D Solvay process
Show answer
Correct answer: (A) Contact process
The contact process oxidises sulphur dioxide to sulphur trioxide over a vanadium pentoxide catalyst and absorbs it to give H2SO4. The Solvay process makes washing soda and the Ostwald process makes nitric acid.
-
Q.329
When two bodies collide and no external force acts on them, which quantity is always conserved?
- A Total kinetic energy of the bodies
- B Velocity of each body
- C Total momentum of the bodies
- D Momentum of each body
Show answer
Correct answer: (C) Total momentum of the bodies
By the law of conservation of momentum, the total momentum of the two bodies is the same before and after the collision when no external force acts. Kinetic energy is conserved only in elastic collisions, and the individual velocities and momenta change.
-
Q.330
The unique ability of carbon atoms to link with other carbon atoms to form long chains, branched chains and rings is called
- A Isomerism
- B Allotropy
- C Polymerisation
- D Catenation
Show answer
Correct answer: (D) Catenation
Catenation is the self-linking property of carbon; together with its tetravalency it explains the very large number of carbon compounds. Allotropy is the existence of an element in different physical forms, such as diamond and graphite.
-
Q.331
One ampere of electric current is equal to
- A 1 joule per coulomb
- B 1 coulomb per second
- C 1 joule per second
- D 1 volt-second
Show answer
Correct answer: (B) 1 coulomb per second
Current is the rate of flow of charge, I = Q/t, so 1 A = 1 C/s. One joule per coulomb is a volt, and one joule per second is a watt.
-
Q.332
On moving from left to right across a period of the modern periodic table, the atomic radius of the elements generally
- A Increases
- B Remains the same
- C Decreases
- D First decreases and then increases
Show answer
Correct answer: (C) Decreases
Across a period the nuclear charge increases while electrons are added to the same shell, so the electrons are pulled closer to the nucleus and the atomic size decreases. Down a group, atomic size increases because new shells are added.
-
Q.333
The direct change of a gas into a solid, without passing through the liquid state, is called
- A Condensation
- B Freezing
- C Fusion
- D Deposition
Show answer
Correct answer: (D) Deposition
The direct change of a gas into a solid is called deposition (the reverse of sublimation). Condensation is gas to liquid, freezing is liquid to solid and fusion is solid to liquid.
-
Q.334
The metal body of an electric iron is connected to the earth wire so that
- A the iron heats up faster
- B any current leaking to the metal body flows to the earth and the user does not get a severe shock
- C the iron uses less electricity
- D no fuse is needed in the circuit
Show answer
Correct answer: (B) any current leaking to the metal body flows to the earth and the user does not get a severe shock
The earth wire provides a low-resistance path to the ground, so if the live wire touches the metal body, the current flows to earth instead of through the user, and the body stays at the potential of the earth.
-
Q.335
The neutron was discovered by
- A Ernest Rutherford
- B J.J. Thomson
- C James Chadwick
- D Niels Bohr
Show answer
Correct answer: (C) James Chadwick
Chadwick discovered the neutron in 1932. Thomson discovered the electron (1897), Goldstein observed the proton as canal rays, and Rutherford discovered the nucleus.
-
Q.336
An iron nail sinks in water, but a ship made of iron floats. This is because
- A the iron used in ships is lighter than ordinary iron
- B the nail has a greater mass than the ship
- C water exerts no upthrust on the nail
- D the hollow shape of the ship lets it displace water whose weight equals its own weight
Show answer
Correct answer: (D) the hollow shape of the ship lets it displace water whose weight equals its own weight
Because of its hollow shape, a ship has a large volume and an average density less than that of water, so it displaces water equal to its own weight before sinking. The solid nail displaces only a little water, so the upthrust on it is less than its weight.
-
Q.337
Which of the following is an acquired trait that is NOT passed on to the offspring?
- A Colour of the eyes
- B Free or attached earlobes
- C Blood group
- D Strong muscles built up by regular exercise
Show answer
Correct answer: (D) Strong muscles built up by regular exercise
Changes in body (somatic) tissues during a lifetime, such as muscles built by exercise, do not change the DNA of the germ cells, so they are not inherited. Eye colour, earlobe type and blood group are controlled by genes and are inherited.
-
Q.338
Cream is separated from milk in dairies by
- A Filtration
- B Centrifugation
- C Distillation
- D Crystallisation
Show answer
Correct answer: (B) Centrifugation
When milk is spun rapidly in a centrifuge, the denser particles are forced to the bottom and the lighter cream stays on top. The same principle is used in washing machines to squeeze water out of clothes and in blood and urine tests.
-
Q.339
The property of metals by which they can be beaten into thin sheets is called
- A Ductility
- B Malleability
- C Sonority
- D Lustre
Show answer
Correct answer: (B) Malleability
Malleability is the ability to be hammered into thin sheets; gold and silver are the most malleable metals. Ductility is the ability to be drawn into wires, sonority is producing a ringing sound when struck, and lustre is the shine of a metal surface.
-
Q.340
Heat from the Sun reaches the Earth by
- A conduction
- B convection
- C radiation
- D both conduction and convection
Show answer
Correct answer: (C) radiation
The space between the Sun and the Earth is almost empty, and only radiation can transfer heat without a material medium. Conduction and convection both need a medium.
-
Q.341
Fractional distillation is used to separate a mixture of two or more miscible liquids when the difference between their boiling points is
- A More than 100 K
- B Between 50 K and 100 K
- C More than 25 K
- D Less than 25 K
Show answer
Correct answer: (D) Less than 25 K
When the boiling points are close (difference less than 25 K), a fractionating column is needed to separate the liquids. Liquids with a large difference in boiling points, such as acetone and water, can be separated by simple distillation.
-
Q.342
Why are antibiotics not useful for treating the common cold?
- A The common cold is caused by a fungus
- B The common cold is a deficiency disease
- C The common cold is caused by bacteria that no antibiotic can kill
- D The common cold is caused by viruses, and antibiotics do not act on viruses
Show answer
Correct answer: (D) The common cold is caused by viruses, and antibiotics do not act on viruses
Antibiotics block biochemical pathways found in bacteria, such as the making of a cell wall. Viruses do not have these pathways, so antibiotics do not work against viral infections like the common cold.
-
Q.343
Taking the speed of sound as 344 m/s, the minimum distance between the source and a reflecting surface needed to hear a distinct echo is about
- A 10 metres
- B 17 metres
- C 34 metres
- D 50 metres
Show answer
Correct answer: (B) 17 metres
The ear retains a sound for 0.1 s, so the reflected sound must travel 344 x 0.1 = 34.4 m in total (to the wall and back); hence the reflector must be at least about 17 m away.
-
Q.344
In some reptiles, such as turtles, the sex of the young one is decided by
- A the size of the egg
- B the amount of food eaten by the mother
- C sex chromosomes, exactly as in humans
- D the temperature at which the fertilised eggs are kept
Show answer
Correct answer: (D) the temperature at which the fertilised eggs are kept
In some reptiles, such as many turtles, sex is not fixed by sex chromosomes; the temperature at which the fertilised eggs develop decides whether the young will be male or female.
-
Q.345
A hydrometer is used to measure the
- A Relative density of liquids
- B Humidity of air
- C Pressure of liquids
- D Depth of water
Show answer
Correct answer: (A) Relative density of liquids
A hydrometer floats in a liquid and reads its relative density (specific gravity); the lactometer used to test milk is a type of hydrometer. Humidity is measured by a hygrometer.
-
Q.346
Washing soda, used in the glass, soap and paper industries, has the chemical formula
- A CaOCl₂
- B NaHCO₃
- C Na₂CO₃·10H₂O
- D NaCl
Show answer
Correct answer: (C) Na₂CO₃·10H₂O
Washing soda is sodium carbonate decahydrate, Na₂CO₃·10H₂O. NaHCO₃ is baking soda, CaOCl₂ is bleaching powder and NaCl is common salt.
-
Q.347
Which of the following metals is the best conductor of heat?
- A Silver
- B Lead
- C Mercury
- D Iron
Show answer
Correct answer: (A) Silver
Silver and copper are the best conductors of heat. Lead and mercury are comparatively poor conductors of heat, and iron lies in between.
-
Q.348
A vaccine protects us from a disease mainly because it
- A directly kills all the germs present in the body
- B trains the immune system to recognise the germ, so the body fights it quickly in a later infection
- C replaces the blood cells destroyed by the germ
- D works as an antibiotic against both bacteria and viruses
Show answer
Correct answer: (B) trains the immune system to recognise the germ, so the body fights it quickly in a later infection
A vaccine contains a weakened, killed or partial form of a germ that cannot cause the disease. The immune system learns to recognise it and remembers it, so when the real germ enters, it is destroyed quickly before the disease develops.
-
Q.349
Which permanent tissue allows easy bending of plant parts such as leaf stalks and stems without breaking?
- A Parenchyma
- B Sclerenchyma
- C Collenchyma
- D Cork
Show answer
Correct answer: (C) Collenchyma
Collenchyma cells are living, elongated and irregularly thickened at the corners, giving both support and flexibility. Sclerenchyma makes parts hard and stiff, parenchyma mainly stores food, and cork is protective.
-
Q.350
The distance-time graph of a body is a straight line parallel to the time axis. The body is
- A at rest
- B moving with uniform speed
- C moving with uniform acceleration
- D moving with decreasing speed
Show answer
Correct answer: (A) at rest
A line parallel to the time axis means the distance does not change with time, so the body is at rest. Uniform speed gives a straight line inclined to the time axis.
← Previous Page 7 / 10 Next →
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.