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RRB JE CBT-1 2024-25 18 December 2024 Shift 1 GK Questions – with answers & solutions

All 42 GK / GS questions asked in RRB JE CBT-1 2024-25 on 18 December 2024 Shift 1, with correct answers and short solutions, subject-wise: Chemistry, Physics, Biology, Economics, Ancient History, Medieval History.

📚 42 questions🗓️ 18 December 2024⏰ Shift 1
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Subjects: Chemistry (14) · Physics (10) · Biology (6) · Economics (1) · Ancient History (1) · Medieval History (1) · Current Affairs (3) · Polity (2) · Static GK (2) · Modern History (1) · Geography (1)

Chemistry (14)

Chemical Reactions and Equations · Combination reactions

Q1. Which of the following represents a combination reaction?

  1. (a) NaCl + AgNO₃ → AgCl + NaNO₃
  2. (b) CaO + H₂O → Ca(OH)₂
  3. (c) 2KClO₃ → 2KCl + 3O₂
  4. (d) CaCO₃ → CaO + CO₂
Answer & solution

Answer: (b) CaO + H₂O → Ca(OH)₂

Answer: Option 2 — CaO + H₂O → Ca(OH)₂
Two reactants, calcium oxide and water, join to give a single product, calcium hydroxide — that is a combination reaction.
Revision note — Types of chemical reactions
• Combination: A + B → AB, a single product; e.g. CaO + H₂O → Ca(OH)₂ + heat, 2Mg + O₂ → 2MgO, C + O₂ → CO₂.
• CaO is quicklime; Ca(OH)₂ is slaked lime — its solution is used for whitewashing.
• Decomposition: AB → A + B, the reverse of combination; e.g. CaCO₃ → CaO + CO₂ (thermal), 2KClO₃ → 2KCl + 3O₂.
• Double displacement: ions are exchanged; e.g. NaCl + AgNO₃ → AgCl + NaNO₃ — the white AgCl is a precipitate.
• Decomposition may be thermal (heat), electrolytic (electricity) or photolytic (light: 2AgCl → 2Ag + Cl₂).
• Most combination reactions are exothermic; most decomposition reactions are endothermic.
Also asked from this topic: the reaction type of CaO + H₂O → Ca(OH)₂ + heat (exothermic combination reaction); the observation that confirms a combination reaction (only one new substance is formed).
Environmental Chemistry · Ozone layer and its depletion

Q2. In which year did the amount of ozone begin to drop sharply in the atmosphere?

  1. (a) 1950
  2. (b) 1970
  3. (c) 1980
  4. (d) 1960
Answer & solution

Answer: (c) 1980

Answer: Option 3 — 1980
The amount of ozone in the atmosphere began to drop sharply in the 1980s, a fall linked to synthetic chemicals like chlorofluorocarbons (CFCs).
Revision note — Ozone layer and its depletion
• Ozone (O₃) is formed in the upper atmosphere when UV splits O₂: O₂ → O + O, then O + O₂ → O₃.
• It lies mainly in the stratosphere and shields the Earth from harmful UV radiation (which can cause skin cancer).
• CFCs, used as refrigerants and in fire extinguishers, release chlorine that destroys ozone; halons release bromine.
• The ozone hole was first reported over Antarctica in 1985.
• In 1987, UNEP forged an agreement to freeze CFC production at 1986 levels; the Montreal Protocol (1987) phases out ozone-depleting substances.
• World Ozone Day is observed on 16 September.
Also asked from this topic: where the ozone hole was first found (Antarctica); the main ozone-depleting chemical (CFCs); the treaty phasing out ozone-depleting substances (Montreal Protocol).
Environmental Chemistry · Acid rain

Q3. Why is monitoring pH crucial for understanding the impacts of acid rain on soil and water ecosystems?

  1. (a) Acid rain decreases the pH, harming aquatic life and soil nutrient availability.
  2. (b) Acid rain does not affect soil and water ecosystems.
  3. (c) Acid rain increases the pH of soil and water bodies.
  4. (d) Acid rain only makes the water taste sour.
Answer & solution

Answer: (a) Acid rain decreases the pH, harming aquatic life and soil nutrient availability.

Answer: Option 1 — Acid rain decreases the pH, harming aquatic life and soil nutrient availability.
Acid rain carries sulphuric and nitric acid, so it lowers the pH of lakes and soil; fish and other organisms survive only in a narrow pH range, and acidic soil loses nutrients.
Revision note — Acid rain
• Rain with pH below 5.6 is called acid rain.
• Caused mainly by sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) from burning fossil fuels; they form H₂SO₄ and HNO₃.
• When the pH of river water falls, the survival of aquatic animals becomes difficult — living organisms tolerate only a narrow pH range (7.0 to 7.8) in the body.
• Acidic soil leaches nutrients such as calcium and magnesium; farmers add quicklime (CaO) or slaked lime to neutralise it.
• Acid rain corrodes marble — the Taj Mahal is affected by SO₂ from the Mathura refinery ("marble cancer").
Also asked from this topic: the gas mainly responsible for acid rain (sulphur dioxide); the two gases that cause acid rain (sulphur dioxide and nitrogen oxides).
Acids, Bases and Salts · pH scale and its importance

Q4. A solution has a pH of 12. Which ion concentration is higher in this solution?

  1. (a) More number S^(2-) ions and more Cl^(-1)
  2. (b) Only H^(+)
  3. (c) Only OH^(−)
  4. (d) Both H^(+ )and OH^(−) are equal
Answer & solution

Answer: (c) Only OH^(−)

Answer: Option 3 — Only OH^(−)
pH 12 is above 7, so the solution is basic — the hydroxide ion (OH^(−)) concentration is higher.
(H^(+) ions are still present, but only about 10^(−12) mol/L against 10^(−2) mol/L of OH^(−); "only" means only OH^(−) is in excess.)
Revision note — pH scale
• pH measures the hydrogen ion concentration; scale runs from 0 to 14.
• pH < 7: acidic (more H^(+)); pH = 7: neutral (pure water); pH > 7: basic (more OH^(−)).
• The lower the pH, the stronger the acid; the higher the pH, the stronger the base.
• At 25 °C, pH + pOH = 14 — pH 12 means pOH 2.
• Everyday values: gastric juice ≈ 1–2, lemon juice ≈ 2.5, pure water 7, blood ≈ 7.4, milk of magnesia ≈ 10, NaOH solution ≈ 14.
• Universal indicator shows pH by colour — red (strong acid) to violet (strong base).
Also asked from this topic: the substance that is neutral on the pH scale (pure water).
Chemical Reactions and Equations · Oxidation, reduction and redox reactions

Q5. In the reaction CuO+H_(2)→Cu+H_(2)O, the substance reduced is:

  1. (a) CuO
  2. (b) Cu
  3. (c) H_(2)O
  4. (d) H_(2)
Answer & solution

Answer: (a) CuO

Answer: Option 1 — CuO
CuO loses oxygen and becomes copper, so CuO is reduced.
Hydrogen gains oxygen and becomes water, so H_(2) is oxidised.
Revision note — Oxidation and reduction (Class 10)
• Oxidation: gain of oxygen or loss of hydrogen.
• Reduction: loss of oxygen or gain of hydrogen.
• A redox reaction has both at once — one substance is oxidised while the other is reduced.
• Oxidising agent = the substance that gives oxygen (and itself gets reduced) — here CuO.
• Reducing agent = the substance that takes oxygen (and itself gets oxidised) — here H_(2).
• Copper heated in air turns black (2Cu + O_(2) → 2CuO); passing hydrogen over hot CuO gives back reddish-brown copper.
Do not mix these up
• Substance reduced vs reducing agent — the substance reduced is CuO; the reducing agent is H_(2).
Also asked from this topic: the substance reduced when MnO_(2) reacts with HCl (MnO_(2)) and the one oxidised (HCl); the reducing agent that extracts zinc from zinc oxide (carbon).
Acids, Bases and Salts · pH scale and its importance

Q6. If a substance has a pH of 11, which of the following statements is true?

  1. (a) It is acidic and does not change the colour of the litmus paper.
  2. (b) It is neutral and does not change the litmus colour.
  3. (c) It is basic and can turn red litmus paper blue.
  4. (d) It is acidic and can turn blue litmus paper red.
Answer & solution

Answer: (c) It is basic and can turn red litmus paper blue.

Answer: Option 3 — It is basic and can turn red litmus paper blue.
A pH above 7 means the solution is basic; pH 11 is a fairly strong base.
Bases turn red litmus blue.
Revision note — The pH scale (Class 10)
• pH runs from 0 to 14: below 7 acidic, 7 neutral, above 7 basic.
• pH = −log[H⁺] — more H⁺ ions, lower pH; each unit step is a 10-times change in H⁺.
• Acids turn blue litmus red; bases turn red litmus blue.
• Phenolphthalein is colourless in acid and pink in base; methyl orange is red in acid and yellow in base.
• Common values: gastric juice about 1–2, lemon juice about 2.2, pure water 7, blood 7.4, milk of magnesia about 10, NaOH solution about 14.
• Tooth decay starts when mouth pH falls below 5.5.
Also asked from this topic: the neutral substance on the pH scale (pure water); what more H⁺ ions do to pH (lower it); the colour of phenolphthalein in a base (pink).
Environmental Chemistry · Water pollution and hardness of water

Q7. Which of the following can be minimised through the implementation of proper sewage treatment?

  1. (a) Air pollution
  2. (b) Water pollution
  3. (c) Noise pollution
  4. (d) Soil pollution
Answer & solution

Answer: (b) Water pollution

Answer: Option 2 — Water pollution
Untreated sewage carries organic waste, pathogens and nutrients into rivers and lakes.
Treating it before discharge directly reduces water pollution.
Revision note — Sewage treatment and water pollution
• Primary treatment: physical removal of solids — screening, grit removal, sedimentation (sludge settles).
• Secondary (biological) treatment: aerobic bacteria digest the organic matter; this lowers the BOD (biochemical oxygen demand).
• Tertiary treatment: removes nitrates, phosphates; disinfection with chlorine or ozone / UV.
• Sludge is digested anaerobically to give biogas (mainly methane).
• High BOD = more organic pollution; clean water has low BOD.
• Excess nitrogen and phosphorus from sewage and fertilisers cause eutrophication — algal blooms and fish death from low dissolved oxygen.
Also asked from this topic: a non-point source of water pollution (agricultural runoff); the nutrients behind eutrophication (nitrogen and phosphorus); the disinfectant used for water and sewage (chlorine).
Chemical Reactions and Equations · Decomposition reactions (thermal, electrolytic, photolytic)

Q8. When lead nitrate is heated, it decomposes to form lead monoxide (PbO), nitrogen dioxide (NO₂), and oxygen (O₂). The brown gas seen during the reaction is:

  1. (a) lead monoxide (PbO)
  2. (b) nitrogen dioxide (NO₂)
  3. (c) nitric oxide (NO)
  4. (d) oxygen (O₂)
Answer & solution

Answer: (b) nitrogen dioxide (NO₂)

Answer: Option 2 — nitrogen dioxide (NO_(2))
On heating, lead nitrate gives brown fumes of nitrogen dioxide (NO_(2)).
2Pb(NO_(3))_(2) → 2PbO + 4NO_(2) + O_(2)
PbO is a yellow solid and O_(2) is colourless.
Revision note — Thermal decomposition (NCERT Class 10, Ch 1)
• Decomposition: one compound breaks into simpler substances — by heat, light or electricity.
• CaCO_(3) → CaO + CO_(2) on heating — quicklime for cement; a thermal decomposition.
• 2FeSO_(4) → Fe_(2)O_(3) + SO_(2) + SO_(3) — green crystals turn reddish-brown, with a smell of burning sulphur.
• 2AgCl → 2Ag + Cl_(2) in sunlight — white turns grey; used in black-and-white photography (photolytic).
• Electrolysis of water: H_(2) and O_(2) in the ratio 2 : 1 by volume (electrolytic).
• Decomposition reactions are mostly endothermic — they need energy.
Also asked from this topic: the energy forms that drive decomposition (heat, light or electricity); the type of reaction when a single compound breaks into simpler substances (decomposition).
Chemical Reactions and Equations · Double displacement and precipitation reactions

Q9. Which of the following combinations would produce a precipitate?

  1. (a) NaOH + Na₂SO₄
  2. (b) NaOH + NaCl
  3. (c) NaCl + KNO₃
  4. (d) NaOH + FeCl₃
Answer & solution

Answer: (d) NaOH + FeCl₃

Answer: Option 4 — NaOH + FeCl_(3)
The ions exchange partners and iron(III) hydroxide, which is insoluble, separates out.
FeCl_(3) + 3NaOH → Fe(OH)_(3)↓ (reddish-brown) + 3NaCl
In the other mixtures every possible product is a sodium or potassium salt, which stays dissolved.
Revision note — Precipitation (double displacement) reactions
• Double displacement: two compounds exchange ions — AB + CD → AD + CB.
• Precipitate: the insoluble solid formed in such a reaction; shown by ↓ or (s).
• Na_(2)SO_(4) + BaCl_(2) → BaSO_(4)↓ (white) + 2NaCl — the NCERT example.
• Pb(NO_(3))_(2) + 2KI → PbI_(2)↓ (yellow) + 2KNO_(3).
• With NaOH: Cu^(2+) gives a blue ppt, Fe^(2+) a green ppt, Fe^(3+) a reddish-brown ppt.
• Solubility rule: all sodium, potassium, ammonium salts and all nitrates are soluble in water.
Also asked from this topic: the white product when barium chloride is mixed with sodium sulphate (barium sulphate, a precipitate); the state symbol of BaSO_(4) in that reaction ((s)).
Environmental Chemistry · Ozone layer and its depletion

Q10. What is the reason for CFC free refrigerators being manufactured for use throughout the world?

  1. (a) CFC is cheap for use in refrigerators.
  2. (b) CFC makes refrigeration a tough process.
  3. (c) CFC is a synthetic chemical which depletes the ozone layer.
  4. (d) CFC is tough to handle for the refrigeration industry.
Answer & solution

Answer: (c) CFC is a synthetic chemical which depletes the ozone layer.

Answer: Option 3 — CFC is a synthetic chemical which depletes the ozone layer.
Chlorofluorocarbons (CFCs) are man-made chemicals once used as refrigerants.
In the stratosphere, UV light breaks them to release chlorine atoms, which destroy ozone (O_(3)).
So refrigerators are now made CFC-free.
Revision note — Ozone layer and its depletion (NCERT Class 10)
• Ozone (O_(3)) — three oxygen atoms; a deadly poison at ground level but a shield in the stratosphere.
• The ozone layer absorbs ultraviolet (UV) radiation, which causes skin cancer and harms living beings.
• Formation: O_(2) + UV → O + O; then O + O_(2) → O_(3).
• Ozone levels fell sharply in the 1980s; the ozone hole was first reported over Antarctica (1985).
• UNEP agreement (1987) froze CFC production at 1986 levels — the Montreal Protocol.
• CFCs were used in refrigerators, air conditioners, aerosol sprays and fire extinguishers.
• World Ozone Day: 16 September.
Also asked from this topic: the compound mainly responsible for ozone depletion (chlorofluorocarbons); the devices that earlier used CFCs extensively (refrigerators); the halogen released by CFCs (chlorine).
Environmental Chemistry · Ozone layer and its depletion

Q11. Which synthetic chemicals are responsible for the depletion of ozone in the atmosphere?

  1. (a) Chlorofluorocarbons (CFCs)
  2. (b) Nitrogen oxides
  3. (c) Methane
  4. (d) Carbon dioxide
Answer & solution

Answer: (a) Chlorofluorocarbons (CFCs)

Answer: Option 1 — Chlorofluorocarbons (CFCs)
CFCs are man-made compounds of chlorine, fluorine and carbon.
In the stratosphere, UV rays break them to release chlorine atoms, which destroy ozone (O_(3)).
Revision note — The ozone layer
• Ozone (O_(3)) is formed in the upper atmosphere when UV splits O_(2) and a free O atom joins O_(2).
• The ozone layer lies in the stratosphere and absorbs harmful UV radiation from the Sun.
• CFCs were used as refrigerants (refrigerators, ACs) and in fire extinguishers and aerosol sprays.
• One chlorine atom can destroy thousands of ozone molecules.
• The ozone hole was first found over Antarctica (reported 1985).
• The Montreal Protocol (1987) phases out ozone-depleting substances.
• World Ozone Day: 16 September.
Do not mix these up
• Ozone depletion vs global warming — ozone loss is caused mainly by CFCs; global warming mainly by CO_(2) and methane.
Also asked from this topic: where the ozone hole was first discovered (Antarctica); the agreement that phases out ozone-depleting substances (Montreal Protocol).
Chemical Reactions and Equations · Double displacement and precipitation reactions

Q12. Which of the following reactions is an example of a precipitation reaction?

  1. (a) NaCl + AgNO_(3) → NaNO_(3) + AgCl
  2. (b) 2H_(2) + O_(2) → 2H_(2)O
  3. (c) CaCO_(3) → CaO + CO_(2)
  4. (d) HCl + NaOH → NaCl + H_(2)O
Answer & solution

Answer: (a) NaCl + AgNO_(3) → NaNO_(3) + AgCl

Answer: Option 1 — NaCl + AgNO_(3) → NaNO_(3) + AgCl
The two salts exchange ions, and silver chloride (AgCl) forms as an insoluble white solid.
An insoluble solid that separates out is a precipitate, so this is a precipitation reaction.
Revision note — Types of chemical reactions
• Precipitation: two solutions give an insoluble solid; e.g. Na_(2)SO_(4) + BaCl_(2) → BaSO_(4)↓ (white) + 2NaCl.
• Every precipitation reaction is a double displacement reaction (ions exchanged).
• Combination: 2H_(2) + O_(2) → 2H_(2)O — two substances form one.
• Decomposition: CaCO_(3) → CaO + CO_(2) on heating (thermal decomposition).
• Neutralisation: HCl + NaOH → NaCl + H_(2)O — acid + base → salt + water.
• AgCl turns grey in sunlight (2AgCl → 2Ag + Cl_(2)) — photolytic decomposition, used in black-and-white photography.
Also asked from this topic: the product formed when barium chloride and sodium sulphate solutions are mixed (a precipitate of barium sulphate).
HCl + NaOH is also a double displacement, but water is not a precipitate — look for the insoluble solid.
Acids, Bases and Salts · Properties of acids

Q13. Which ion is responsible for the acidic properties of acids?

  1. (a) Cl^(−)
  2. (b) OH^(−)
  3. (c) H^(+)
  4. (d) Na^(+)
Answer & solution

Answer: (c) H^(+)

Answer: Option 3 — H^(+)
Acids release hydrogen ions (H^(+)) when dissolved in water.
These H^(+) ions give acids their sour taste, turn blue litmus red and react with metals and bases.
Revision note — Acids and their ions
• H^(+) cannot exist alone; it joins water to form the hydronium ion (H_(3)O^(+)).
• Acids show acidic behaviour only in water — dry HCl gas does not change dry litmus.
• Bases/alkalis give hydroxide ions (OH^(−)) in water.
• Neutralisation: H^(+) + OH^(−) → H_(2)O.
• More H^(+) ⇒ lower pH; acids have pH < 7.
• Strong acids (HCl, H_(2)SO_(4), HNO_(3)) ionise fully; weak acids (acetic acid) ionise partly.
Do not mix these up
• H^(+) vs OH^(−) — H^(+) makes a solution acidic; OH^(−) makes it basic.
Also asked from this topic: the ion H^(+) is always shown as (hydronium ion, H_(3)O^(+)); why an acid shows acidic behaviour only in water (H^(+) ions form only on dissolving).
Chemical Reactions and Equations · Combination reactions

Q14. When two elements react to form a compound, it can be classified as:

  1. (a) combination
  2. (b) displacement
  3. (c) double displacement
  4. (d) decomposition
Answer & solution

Answer: (a) combination

Answer: Option 1 — combination
When two or more substances join to form a single new product, it is a combination reaction (A + B → AB).
Two elements forming a compound is the simplest case, e.g. C + O_(2) → CO_(2).
Revision note — Types of chemical reactions
• Combination: A + B → AB; e.g. CaO + H_(2)O → Ca(OH)_(2) + heat (quicklime to slaked lime).
• Decomposition: AB → A + B; needs heat, light or electricity.
• Displacement: a more reactive element pushes out a less reactive one; e.g. Fe + CuSO_(4) → FeSO_(4) + Cu.
• Double displacement: ions are exchanged; e.g. Na_(2)SO_(4) + BaCl_(2) → BaSO_(4) + 2NaCl.
• Most combination reactions are exothermic (release heat).
• Burning of coal and formation of water from H_(2) and O_(2) are combination reactions.
Do not mix these up
• Combination vs decomposition — combination makes one product from many; decomposition breaks one reactant into many.
Also asked from this topic: the type of reaction CaO + H_(2)O → Ca(OH)_(2) + heat (combination reaction); the observation that confirms a combination reaction (a single product forms from two or more reactants).

Physics (10)

Electricity · Resistance, resistivity and their factors

Q15. What happens to the resistance of most conductors as their temperature increases?

  1. (a) It decreases.
  2. (b) It remains the same.
  3. (c) It increases.
  4. (d) It becomes zero.
Answer & solution

Answer: (c) It increases.

Answer: Option 3 — It increases.
In a metal, heat makes the ions vibrate more, so the free electrons collide more often — the resistance rises with temperature.
Revision note — Factors affecting resistance
• R = ρL ÷ A — resistance is directly proportional to length and inversely proportional to area of cross-section.
• ρ (resistivity) depends on the material and temperature, not on the size of the wire; SI unit Ω m.
• For metals, resistance increases with temperature; for semiconductors (silicon, germanium) it decreases.
• Alloys (nichrome, manganin, constantan) have higher resistivity and change little with temperature — used in heating elements and standard resistors.
• Superconductors have zero resistance below a critical temperature.
• Good conductors: silver (lowest resistivity), then copper, aluminium.
Do not mix these up
• Metal vs semiconductor — heating raises a metal's resistance but lowers a semiconductor's.
Also asked from this topic: why alloys are used in toaster heating elements (higher resistivity, do not oxidise readily); the copper alloy used for standard resistors (manganin).
Magnetism and Magnetic Effects of Current · Electric generator and Fleming's right-hand rule

Q16. Fleming's Right-Hand Rule is applicable in the case of _________.

  1. (a) electric motors
  2. (b) fuse wires
  3. (c) electric kettles
  4. (d) electric generators
Answer & solution

Answer: (d) electric generators

Answer: Option 4 — electric generators
Fleming's right-hand rule gives the direction of the induced current when a conductor moves in a magnetic field — the principle of the electric generator.
Revision note — Fleming's rules and electromagnetic induction
• Right hand: thumb = motion of conductor, forefinger = magnetic field, middle finger = induced current — all three mutually perpendicular.
• Generator converts mechanical energy → electrical energy; works on electromagnetic induction (Faraday).
• Fleming's left-hand rule gives the direction of force on a current-carrying conductor — used for the electric motor (electrical → mechanical).
• AC generator uses slip rings; DC generator and DC motor use a split-ring commutator.
• Induced current is larger when the coil turns faster, has more turns, or the field is stronger.
• In India, AC is supplied at 220 V, 50 Hz.
Do not mix these up
• Right hand = generator (current is produced) · left hand = motor (force is produced).
Also asked from this topic: the part that makes an AC generator's output alternate (slip rings); the effect of doubling the speed of rotation of a generator coil (induced potential difference doubles).
Electricity · Resistance, resistivity and their factors

Q17. A copper wire has a resistance of 10 Ω. If it is replaced with a wire of the same material and length but twice the cross-sectional area, its resistance will be ______.

  1. (a) 10 Ω
  2. (b) 2.5 Ω
  3. (c) 20 Ω
  4. (d) 5 Ω
Answer & solution

Answer: (d) 5 Ω

Rule — R = ρL ÷ A.
Same material ⇒ same ρ; same length.
So resistance is inversely proportional to the area of cross-section.
New resistance.
Area becomes 2A ⇒ R becomes R ÷ 2
R₂ = 10 ÷ 2 = 5 Ω
Answer: 5 Ω
Revision note — Resistance of a wire
• R ∝ L — doubling the length doubles the resistance.
• R ∝ 1 ÷ A — a thicker wire has less resistance.
• Stretching a wire to n times its length (volume fixed) makes the resistance n² times.
• ρ depends only on the material and temperature; unit Ω m.
Thicker wire, easier path — doubling the area halves the resistance, it does not double it.
Electricity · Resistors in series and parallel

Q18. If three resistors of 6 Ω, 3 Ω and 2 Ω are connected in parallel, the total equivalent resistance is ________.

  1. (a) 11 Ω
  2. (b) 2 Ω
  3. (c) 1 Ω
  4. (d) 0.5 Ω
Answer & solution

Answer: (c) 1 Ω

Formula — resistors in parallel.
The reciprocal of the equivalent resistance equals the sum of the reciprocals.
1/R = 1/R₁ + 1/R₂ + 1/R₃
Substitute.
1/R = 1/6 + 1/3 + 1/2
= 1/6 + 2/6 + 3/6
= 6/6 = 1
R = 1 Ω
Answer: 1 Ω
Revision note — Series and parallel combinations
• Series: R = R₁ + R₂ + R₃; the same current flows through each resistor.
• Parallel: 1/R = 1/R₁ + 1/R₂ + 1/R₃; the same potential difference is across each resistor.
• The parallel equivalent is always less than the smallest resistor (here 1 Ω < 2 Ω).
• Two resistors in parallel: R = (R₁ × R₂) ÷ (R₁ + R₂).
• Household wiring is in parallel — each appliance gets the full voltage and works independently.
Also asked from this topic: 4 Ω, 6 Ω and 12 Ω in parallel (2 Ω); a wire of resistance R cut in half and the halves joined in parallel (R/4); what is the same across resistors in parallel (voltage).
11 Ω is the series total — in parallel the answer must be below the smallest resistor, 2 Ω.
Electricity · Resistance, resistivity and their factors

Q19. If the length of a wire-shaped resistor is doubled, the resistivity:

  1. (a) remains the same
  2. (b) is halved
  3. (c) is quadrupled
  4. (d) is doubled
Answer & solution

Answer: (a) remains the same

Answer: Option 1 — remains the same
Resistivity (ρ) is a property of the material (and its temperature), not of the wire's size.
Doubling the length doubles the resistance, but the resistivity stays unchanged.
Revision note — Resistance and resistivity
• R = ρ l ÷ A — resistance is directly proportional to length and inversely proportional to area.
• SI unit of resistivity: ohm metre (Ω m); of resistance: ohm (Ω).
• Resistivity changes only with the material and temperature.
• Metals and alloys: 10^(−8) to 10^(−6) Ω m; insulators (glass, rubber): 10^(12) to 10^(17) Ω m.
• Alloys (nichrome) have higher resistivity than their metals and do not oxidise easily — used in heaters, irons, toasters.
• Copper and aluminium have low resistivity — used for transmission wires.
Do not mix these up
• Resistance vs resistivity — cutting, stretching or thickening a wire changes its resistance; its resistivity stays the same.
• Stretching a wire to double length: area halves, so resistance becomes 4 times; resistivity is still unchanged.
Also asked from this topic: new resistance when a 4 Ω wire is stretched to double its length (16 Ω); why nichrome is used as a heating element (high resistivity and high melting point).
Magnetism and Magnetic Effects of Current · Force on a current-carrying conductor and Fleming's left-hand rule

Q20. In which direction does the force act on a conductor placed in a magnetic field in an electric motor?

  1. (a) Perpendicular to both the current and magnetic field
  2. (b) Along the magnetic field
  3. (c) In the direction of the current
  4. (d) Opposite to the magnetic field
Answer & solution

Answer: (a) Perpendicular to both the current and magnetic field

Answer: Option 1 — Perpendicular to both the current and magnetic field
By Fleming's left-hand rule, the force on a current-carrying conductor in a magnetic field acts at right angles to both the current and the field.
This force is what turns the coil of an electric motor.
Revision note — Force on a conductor and the electric motor
• Fleming's left-hand rule: forefinger → field, middle finger → current, thumb → force (motion), all mutually perpendicular.
• Force F = BIL sin θ: maximum when current ⊥ field, zero when current ∥ field.
• Reversing either the current or the field reverses the force.
• An electric motor converts electrical energy → mechanical energy.
• The split-ring commutator reverses the current in the coil every half rotation, so the coil keeps turning one way.
• Parts of a motor: armature coil, field magnet, split rings, carbon brushes.
Do not mix these up
• Left-hand vs right-hand rule — left hand gives the force in a motor; right hand gives the induced current in a generator.
Also asked from this topic: the finger that shows the field in Fleming's left-hand rule (index finger); the force when the current is reversed (it reverses); doubling the current (force doubles).
Electricity · Ohm's law

Q21. The potential difference versus current plot for a conducting wire is a straight line. The slope of this line gives us the:

  1. (a) number of electrons in the wire
  2. (b) voltage across the wire
  3. (c) resistance of the wire
  4. (d) current flowing through the wire
Answer & solution

Answer: (c) resistance of the wire

Answer: Option 3 — resistance of the wire
By Ohm's law, V = IR, so V/I is constant for a given wire.
On a V (y-axis) versus I (x-axis) graph, the slope = V/I = R, the resistance.
Revision note — Ohm's law
• Ohm's law: at constant temperature, V ∝ I, i.e. V = IR.
• The V–I graph of an ohmic conductor is a straight line through the origin.
• Steeper V–I line ⇒ higher resistance.
• If I is on the y-axis and V on the x-axis, the slope is 1/R (conductance).
• SI unit of resistance: ohm (Ω); 1 Ω = 1 V/1 A.
• R depends on length (R ∝ l), area (R ∝ 1/A), material and temperature: R = ρl/A.
Do not mix these up
• V–I vs I–V graph — slope of V against I is R; slope of I against V is 1/R.
Also asked from this topic: the shape of the graph that represents Ohm's law (a straight line through the origin); the unit volt per ampere (ohm).
Electricity · Electric power and electrical energy

Q22. Which of the following will cause the greatest increase in power dissipation for a given resistor?

  1. (a) Halving the resistance
  2. (b) Doubling the voltage across the resistor
  3. (c) Doubling the resistance
  4. (d) Halving the current through the resistor
Answer & solution

Answer: (b) Doubling the voltage across the resistor

Answer: Option 2 — Doubling the voltage across the resistor
Power in a resistor: P = V²/R = I²R.
Doubling V ⇒ P = (2V)²/R = 4 times, the largest rise of the four.
Revision note — Electric power
• P = VI = I²R = V²/R; SI unit watt (W); 1 W = 1 V × 1 A.
• Commercial unit of energy: kilowatt-hour (kWh) = 3.6 × 10^(6) J = 1 "unit".
• Energy = Power × Time.
• P ∝ square of V or I, so doubling either gives 4 times the power; halving either gives one-fourth.
• At fixed V, P ∝ 1/R — halving R only doubles the power.
• Heat produced (Joule's law): H = I²Rt.
Also asked from this topic: the formula for electrical energy (Energy = Power × Time); how to reduce power without changing current (decrease the resistance); resistance of a 60 W bulb at 120 V (240 Ω).
Power goes as the square of voltage — doubling V gives four times, not two times, the power.
Magnetism and Magnetic Effects of Current · Force on a current-carrying conductor and Fleming's left-hand rule

Q23. According to experimental results, when does the magnitude of the force on a current-carrying conductor in a magnetic field become the highest?

  1. (a) When the current is opposite to the magnetic field
  2. (b) When the current is parallel to the magnetic field
  3. (c) When the current is perpendicular to the magnetic field
  4. (d) When the current flows at any angle to the magnetic field
Answer & solution

Answer: (c) When the current is perpendicular to the magnetic field

Answer: Option 3 — When the current is perpendicular to the magnetic field
Force on the conductor: F = BIL sin θ, θ = angle between current and field.
sin θ is largest (1) at θ = 90°, so the force is maximum when current ⊥ field.
Revision note — Force on a current-carrying conductor
• Discovered with the "rod-in-magnet" experiment; basis of the electric motor.
• θ = 0° (parallel) or 180° (opposite) ⇒ sin θ = 0 ⇒ no force.
• Force doubles when the current or the field doubles.
• Direction by Fleming's left-hand rule: forefinger → field, middle finger → current, thumb → force.
• Reversing the current or the field reverses the force.
Do not mix these up
• Opposite to the field is still along the field line (θ = 180°) — the force is zero, not maximum.
Also asked from this topic: the effect of doubling the current in a conductor perpendicular to the field (the force doubles); the finger that shows the field in Fleming's left-hand rule (index finger).
Magnetism and Magnetic Effects of Current · Magnetic field and field lines

Q24. Why do iron filings arrange themselves in a pattern around a bar magnet?

  1. (a) Due to gravitational force
  2. (b) Because of the magnetic field
  3. (c) Because they are heavy
  4. (d) Due to electric charge
Answer & solution

Answer: (b) Because of the magnetic field

Answer: Option 2 — Because of the magnetic field
The region around a magnet has a magnetic field.
Each iron filing becomes a tiny magnet in this field and lines up along the field lines, making the pattern.
Revision note — Magnetic field and field lines
• Field lines go from the north pole to the south pole outside the magnet and S to N inside — they are closed curves.
• Two field lines never cross — else the field would have two directions at one point.
• Closer lines = stronger field; lines are crowded near the poles.
• A compass needle placed on a line points along it; its north end shows the field direction.
• Magnetic field is a vector: it has both magnitude and direction.
• SI unit of magnetic field: tesla (T).
Also asked from this topic: what crowded field lines indicate (a stronger magnetic field); what the deflection of a compass near a current-carrying wire shows (a magnetic field around the wire).
The filings are pulled by magnetism, not by gravity or electric charge — iron is magnetic, not charged.

Biology (6)

Ecology and Environment · Waste management and biodegradable substances

Q25. Which of the following can be broken down by biological processes?

  1. (a) Vegetable peels
  2. (b) Milk packets
  3. (c) Aluminium foil
  4. (d) Plastic bottles
Answer & solution

Answer: (a) Vegetable peels

Answer: Option 1 — Vegetable peels
Vegetable peels are plant matter that bacteria and fungi (decomposers) break down — so they are biodegradable.
Milk packets, aluminium foil and plastic bottles are not broken down by microbes.
Revision note — Biodegradable and non-biodegradable substances
• Biodegradable: broken down by biological processes — vegetable peels, paper, wood, cotton, dry leaves, dead animals.
• Non-biodegradable: remain for long periods — plastics, polythene, glass, aluminium, DDT, styrofoam.
• Microbes act through enzymes, which are specific — they cannot break plastics.
• Non-biodegradable chemicals like DDT concentrate up the food chain — biological magnification.
• 3Rs: Reduce, Reuse, Recycle; kitchen waste can be turned into compost or biogas.
Also asked from this topic: an example of biodegradable waste (dead animals); the commonest non-biodegradable waste (plastic); an example of "reducing" in waste management (switching from plastic bags to jute bags).
Ecology and Environment · Waste management and biodegradable substances

Q26. Which of the following substances will take the longest time to degrade naturally in the environment?

  1. (a) Cardboard box
  2. (b) Paper
  3. (c) Leather
  4. (d) Leaves
Answer & solution

Answer: (c) Leather

Answer: Option 3 — Leather
Leather is biodegradable, but tanning cross-links its protein fibres so microbes break it down very slowly — it can take decades.
Paper, cardboard and leaves are plant cellulose and rot within weeks to a few months.
Revision note — Biodegradable and non-biodegradable waste (Class 10)
• Biodegradable: broken down by bacteria and fungi (decomposers) — food waste, paper, leaves, cotton, wood, leather, dead animals.
• Non-biodegradable: cannot be broken down by microbes — plastics, polythene, glass, aluminium cans, DDT, many metals.
• Non-biodegradable chemicals such as DDT build up along food chains — biological magnification; the top consumer gets the highest dose.
• Rough decay times: paper and leaves — weeks to months; cotton cloth — months; leather — decades; plastic — hundreds of years; glass — practically never.
• 3 Rs: Reduce (e.g. jute bag instead of plastic), Reuse, Recycle.
Also asked from this topic: the commonest non-biodegradable waste (plastic); an example of biodegradable waste (dead animals, food scraps); an example of "reduce" (jute bags instead of plastic).
Ecology and Environment · Waste management and biodegradable substances

Q27. Which attribute of a paper cup makes it better than a plastic cup for our environment?

  1. (a) Disposable
  2. (b) Non-biodegradable
  3. (c) Biodegradable
  4. (d) Not disposable
Answer & solution

Answer: (c) Biodegradable

Answer: Option 3 — Biodegradable
A paper cup is made of paper (cellulose), which bacteria and fungi break down into harmless substances.
A plastic cup is non-biodegradable — it stays in soil and water for hundreds of years.
Revision note — Biodegradable and non-biodegradable substances
• Biodegradable: broken down by biological processes (microorganisms) — paper, vegetable peels, food waste, dry leaves, cotton, wood, dead animals.
• Non-biodegradable: not broken down by microbes — plastics, polythene, glass, aluminium cans, DDT, many pesticides.
• Non-biodegradable chemicals such as DDT enter food chains and show biological magnification — highest at the top trophic level.
• Plastics clog drains, harm aquatic and grazing animals and choke soil.
• 3 Rs: Reduce (use less), Reuse (use again), Recycle (reprocess into new products).
• Kulhads (disposable clay cups) were once suggested for trains; making them on a large scale would waste fertile top soil.
Do not mix these up
• Disposable vs biodegradable — both paper and plastic cups are disposable; only the paper cup is biodegradable.
Also asked from this topic: a common non-biodegradable waste (plastic); an effect of non-biodegradable substances in water bodies (they clog drains and harm aquatic life).
Ecology and Environment · Waste management and biodegradable substances

Q28. What term can be used for substances that are broken down by biological processes?

  1. (a) Biodegradable
  2. (b) Recyclable
  3. (c) Compostable
  4. (d) Non-biodegradable
Answer & solution

Answer: (a) Biodegradable

Answer: Option 1 — Biodegradable
Substances that microorganisms (bacteria, fungi) can break down by biological processes are called biodegradable.
Revision note — Biodegradable and non-biodegradable substances
• Biodegradable: broken down by decomposers — food waste, paper, cotton, wood, leaves, animal dung.
• Non-biodegradable: inert to microbes — plastic, glass, metal cans, DDT; they persist and pile up.
• Decomposers (bacteria, fungi) return nutrients to the soil and are part of every ecosystem.
• Biological magnification: non-biodegradable chemicals build up along the food chain, highest in top consumers.
• Enzymes are specific — the enzymes of decomposers act only on certain substances, so plastic is not digested.
• Compostable waste is biodegradable waste that turns into manure (compost) under controlled conditions.
Do not mix these up
• Biodegradable vs recyclable — recyclable means reprocessed by humans into new products (glass, metals); biodegradable means broken down by living organisms.
Also asked from this topic: which is biodegradable waste (dead animals); an advantage of paper cups over plastic cups (they are biodegradable).
Ecology and Environment · Ecosystem and its components

Q29. What would happen to dead plants and animals if decomposers were absent from an ecosystem?

  1. (a) They would be eaten by consumers.
  2. (b) They would persist, and the natural replenishment of soil would be hindered.
  3. (c) They would quickly turn into soil.
  4. (d) They would become producers.
Answer & solution

Answer: (b) They would persist, and the natural replenishment of soil would be hindered.

Answer: Option 2 — They would persist, and the natural replenishment of soil would be hindered.
Decomposers (bacteria and fungi) break dead remains into simple inorganic substances that go back to the soil.
Without them, dead bodies would pile up and nutrients would not return to the soil.
Revision note — Decomposers and the ecosystem
• An ecosystem has biotic parts (producers, consumers, decomposers) and abiotic parts (air, water, soil, light, temperature).
• Decomposers break complex organic matter → simple inorganic substances; they are the natural cleaners.
• They recycle nutrients so that producers can use them again.
• Materials broken down by microbes are biodegradable; plastics and DDT are non-biodegradable.
• Energy flows one way; nutrients cycle — decomposers close the nutrient cycle.
Do not mix these up
• Decomposers vs scavengers — vultures and jackals eat carcasses (consumers); bacteria and fungi chemically break down dead matter.
Also asked from this topic: the organisms that break down dead plants and animals (decomposers); the main role of decomposers (recycle nutrients back into the soil).
Ecology and Environment · Trophic levels and the 10 percent law

Q30. What role do green plants and certain bacteria play in an ecosystem?

  1. (a) Consumers
  2. (b) Producers
  3. (c) Parasites
  4. (d) Decomposers
Answer & solution

Answer: (b) Producers

Answer: Option 2 — Producers
Green plants and certain bacteria (such as cyanobacteria) make their own food from simple substances using sunlight — they are autotrophs.
So they are the producers of an ecosystem.
Revision note — Producers and trophic levels
• Producers = autotrophs; they fix solar energy by photosynthesis (some bacteria use chemosynthesis).
• They form the first trophic level; all other organisms depend on them.
• Herbivores are primary consumers; carnivores are secondary/tertiary consumers.
• Decomposers (bacteria, fungi) are saprophytes that break down dead matter.
• 10 percent law: only about 10% of energy passes to the next trophic level.
• Energy flow is unidirectional; a grassland pyramid of numbers is upright (grass most numerous).
Do not mix these up
• Producers vs decomposers — both can be bacteria; producers make food, decomposers break down dead matter.
Also asked from this topic: the group that captures solar energy in a garden ecosystem (plants); the organisms NOT classified as consumers (producers); the trophic level hit hardest by a drought (producers).

Economics (1)

Basic Concepts and Economic Systems · Cost, revenue and utility concepts

Q31. With which of the following pricing approaches is a product's price equal to its marginal cost?

  1. (a) Factor pricing
  2. (b) Mark-up pricing
  3. (c) Price discrimination
  4. (d) Marginal cost pricing
Answer & solution

Answer: (d) Marginal cost pricing

Answer: Option 4 — Marginal cost pricing
Under marginal cost pricing, the price is set equal to the marginal cost (P = MC) — the cost of producing one extra unit.
Revision note — Cost and pricing concepts
• Marginal cost (MC) = change in total cost from producing one more unit.
• Total cost = Total fixed cost + Total variable cost; fixed cost does not change with output.
• In perfect competition, a firm's equilibrium is where P = MR = MC — the efficient (allocative) output.
• Mark-up (cost-plus) pricing: price = average cost + a fixed margin.
• Price discrimination: charging different prices to different buyers for the same good — needs a monopoly.
• Factor pricing: how rewards of factors — rent, wages, interest, profit — are fixed.
• The short-run AC, AVC and MC curves are U-shaped (law of variable proportions); MC cuts AC at its minimum.
Also asked from this topic: the short-run cost curve that is U-shaped due to the law of variable proportions (average variable cost curve).

Ancient History (1)

Ancient Art, Culture and Science · Temple architecture styles (Nagara, Dravida, Vesara)

Q32. What architectural style is the Meenakshi Amman Temple known for?

  1. (a) Gothic
  2. (b) Roman
  3. (c) Indo-Saracenic
  4. (d) Dravidian
Answer & solution

Answer: (d) Dravidian

Answer: Option 4 — Dravidian
The Meenakshi Amman Temple at Madurai (Tamil Nadu) is a classic Dravidian temple, famous for its towering, richly sculpted gopurams.
Revision note — Temple architecture styles of India
• Nagara (north India): curvilinear tower called shikhara, topped by an amalaka — e.g. Kandariya Mahadeva (Khajuraho), Sun Temple (Konark).
• Dravida (south India): pyramidal tower over the sanctum called vimana, huge gateway towers called gopurams, enclosed courtyard and temple tank.
• Dravida examples: Brihadeeswara (Thanjavur) by Rajaraja Chola I, Shore Temple (Mahabalipuram), Meenakshi Temple (Madurai).
• Vesara: a blend of Nagara and Dravida, developed by the Chalukyas and later Hoysalas.
• Meenakshi Temple: originally built by the Pandyas, greatly expanded by the Nayaks (notably Thirumalai Nayak); has 14 gopurams.
• Indo-Saracenic is a colonial style (19th–20th century) — e.g. Victoria Memorial, Gateway of India, Madras High Court.
Do not mix these up
• Vimana vs gopuram — the vimana rises over the sanctum; the gopuram is the gateway tower in the outer wall.
Also asked from this topic: the Meenakshi Temple's famous feature (gigantic gopurams); its nickname (Taj Mahal of the South); the tower over a Dravida sanctum (vimana); Vesara combines (Nagara and Dravida).

Medieval History (1)

Delhi Sultanate · Slave (Mamluk) dynasty

Q33. The first ruler of Delhi Sultanate was:

  1. (a) Alauddin Khalji
  2. (b) Qutb-ud-din Aibak
  3. (c) Balban
  4. (d) Iltutmish
Answer & solution

Answer: (b) Qutb-ud-din Aibak

Answer: Option 2 — Qutb-ud-din Aibak
Qutb-ud-din Aibak, a slave-general of Muhammad Ghori, became the first Sultan of Delhi in 1206 and founded the Slave (Mamluk) dynasty.
Revision note — Delhi Sultanate (1206–1526)
• Five dynasties in order: Slave (Mamluk) → Khalji → Tughlaq → Sayyid → Lodi.
• Aibak (1206–1210): began the Qutub Minar and the Quwwat-ul-Islam mosque; called Lakh Baksh for his generosity; died in 1210 at Lahore after a fall while playing chaugan (polo).
• Iltutmish (1211–1236): completed the Qutub Minar; introduced the silver tanka and copper jital; set up the Turkan-i-Chahalgani (group of forty).
• Balban (1266–1287): theory of kingship, sijda and paibos.
• Alauddin Khalji (1296–1316): market reforms, dagh (branding) and chehra (descriptive roll).
• Founders: Khalji — Jalaluddin Khalji (1290); Tughlaq — Ghiyasuddin Tughlaq (1320); Sayyid — Khizr Khan (1414); Lodi — Bahlol Lodi (1451).
• The Sultanate ended when Babur defeated Ibrahim Lodi at the First Battle of Panipat (1526).
Also asked from this topic: Aibak's reign (1206–1210); how he died (fall while playing chaugan); order of early Turkish rulers (Aibak → Iltutmish → Balban); founder of the Lodi dynasty (Bahlol Lodi).

Current Affairs (3)

International Affairs and Summits · Summits and conferences

Q34. What was the venue of the North Atlantic treaty Organization (NATO) Summit in July 2024?

  1. (a) Washington, D.C., United States
  2. (b) Paris, France
  3. (c) New York, United States
  4. (d) London, England
Answer & solution

Answer: (a) Washington, D.C., United States

Answer: Option 1 — Washington, D.C., United States
The NATO Summit 2024 was held in Washington, D.C. from 9 to 11 July 2024.
It marked the 75th anniversary of NATO, founded by the Washington Treaty of 4 April 1949.
Revision note — NATO
• NATO: North Atlantic Treaty Organization, a military alliance set up in 1949 with 12 founding members.
• Headquarters: Brussels, Belgium; military command SHAPE at Mons, Belgium.
• Article 5: an attack on one member is an attack on all — invoked only once, after 9/11 (2001).
• Newest members: Finland (2023) and Sweden (March 2024), taking the total to 32.
• The 2024 summit was held at the same city where the treaty was signed in 1949.
• As of 2026: the 2025 NATO Summit was held in The Hague, Netherlands (24–25 June 2025).
Also asked from this topic: the summit hosted for the first time by the Netherlands in June 2025 (NATO Summit, The Hague).
Awards and Honours - Current · International awards - current

Q35. For which mission of ISRO has the International Astronautical Federation (IAF) awarded ISRO the World Space Award?

  1. (a) Chandrayaan-2
  2. (b) Aditya-L1
  3. (c) Chandrayaan-3
  4. (d) Venus Mission
Answer & solution

Answer: (c) Chandrayaan-3

Answer: Option 3 — Chandrayaan-3
The International Astronautical Federation (IAF) gave ISRO its World Space Award 2024 for Chandrayaan-3.
The award was presented at the 75th International Astronautical Congress in Milan, Italy (October 2024).
Revision note — Chandrayaan-3
• Launched on 14 July 2023 by LVM3-M4 from Sriharikota.
• Vikram lander soft-landed near the lunar south pole on 23 August 2023.
• India became the 4th country to soft-land on the Moon and the first near its south pole.
• The Pragyan rover moved on the surface; the landing site is named Shiv Shakti Point.
• 23 August is now observed as National Space Day.
• Its LVM3 rocket (earlier GSLV Mk III) is nicknamed Fat Boy.
Do not mix these up
• Chandrayaan-2 vs Chandrayaan-3 — Chandrayaan-2 (2019) orbiter still works but its lander crashed; Chandrayaan-3 landed safely.
• Aditya-L1 — India's first solar mission (launched September 2023), placed around the L1 point, not a Moon mission.
Also asked from this topic: the day India celebrates National Space Day (23 August); the lander and rover of Chandrayaan-3 (Vikram and Pragyan); the agency that supplied its Laser Retroreflector Array (NASA).
Appointments and Resignations · National appointments

Q36. Who was appointed as the new head coach of the junior men’s hockey team in August 2024?

  1. (a) Shankar Lakshman
  2. (b) Prithipal Singh
  3. (c) PR Sreejesh
  4. (d) Harmanpreet Singh
Answer & solution

Answer: (c) PR Sreejesh

Answer: Option 3 — PR Sreejesh
After retiring from international hockey at the Paris Olympics 2024, goalkeeper PR Sreejesh was named head coach of India's junior men's hockey team by Hockey India in August 2024.
Revision note — PR Sreejesh
• Goalkeeper from Kerala; played for India for about 18 years.
• Won Olympic bronze twice — Tokyo 2020 and Paris 2024.
• Paris 2024 bronze was India's second consecutive Olympic hockey medal; Sreejesh retired after it.
• Hockey India retired his jersey number 16 for the senior men's team.
• Received the Major Dhyan Chand Khel Ratna in 2021.
• Harmanpreet Singh captained India at Paris 2024; Craig Fulton was the senior men's head coach.
Also asked from this topic: the award PR Sreejesh received in 2025 for sports (Padma Bhushan).
Sreejesh became the coach, not the captain — Harmanpreet Singh is the senior team's captain.

Polity (2)

Special Provisions, Official Language and Miscellaneous Provisions · Union Territories administration

Q37. Which of the following articles empowers the President to make regulations for the peace, progress and good government of the union territories?

  1. (a) Article 240
  2. (b) Article 243
  3. (c) Article 239
  4. (d) Article 244
Answer & solution

Answer: (a) Article 240

Answer: Option 1 — Article 240
Article 240 empowers the President to make regulations for the peace, progress and good government of certain Union Territories.
Such a regulation has the same force as an Act of Parliament and can repeal or amend a law of Parliament for that UT.
Revision note — Union Territories (Part VIII, Articles 239–242)
• Article 239: every UT is administered by the President through an administrator he appoints (Lt Governor, Administrator).
• Article 239A: local legislature / council of ministers for Puducherry.
• Article 239AA: special provisions for Delhi — added by the 69th Amendment, 1991.
• Article 239B: the administrator's power to issue ordinances when the UT legislature is in recess.
• Article 240 covers Andaman & Nicobar Islands, Lakshadweep, Dadra & Nagar Haveli and Daman & Diu, and Puducherry only when its legislature is dissolved or suspended.
• Article 241: High Courts for Union Territories.
Do not mix these up
• Article 243 is the start of Part IX (Panchayats); Article 244 deals with Scheduled and tribal areas (Fifth and Sixth Schedules).
Also asked from this topic: who administers a Union Territory under Article 239 (the President, through an administrator); the article on the ordinance power of a UT administrator (239B).
DPSP and Fundamental Duties · Fundamental Duties - Article 51A and list

Q38. Article 51 A (b) of the Indian Constitution states that it is the duty of the citizens 'to cherish and follow the noble ideals that inspired the _______'.

  1. (a) global values and principles
  2. (b) customs and traditions of India
  3. (c) political ideas of various parties
  4. (d) national struggle for freedom
Answer & solution

Answer: (d) national struggle for freedom

Answer: Option 4 — national struggle for freedom
Article 51A(b) asks every citizen to cherish and follow the noble ideals which inspired our national struggle for freedom.
Revision note — Fundamental Duties (Article 51A)
• Added in Part IVA by the 42nd Amendment, 1976, on the Swaran Singh Committee's advice; idea taken from the USSR.
• 51A(a) abide by the Constitution, respect the National Flag and National Anthem.
• 51A(c) uphold sovereignty, unity and integrity; 51A(d) defend the country.
• 51A(e) promote common brotherhood; renounce practices derogatory to women.
• 51A(f) value composite culture; 51A(g) protect the natural environment; 51A(h) develop scientific temper.
• 51A(i) safeguard public property; 51A(j) strive for excellence.
• 51A(k) parents to give education to children aged 6–14 — added by the 86th Amendment, 2002 (the 11th duty).
Do not mix these up
• 51A(b) vs 51A(f) — (b) is the ideals of the freedom struggle; (f) is the rich heritage of our composite culture.
Also asked from this topic: the amendment that added Fundamental Duties (42nd Amendment); the duty added by the 86th Amendment (education for ages 6–14); the country from which the idea was borrowed (USSR).

Static GK (2)

Space, Defence and Technology · Launch vehicles and satellites

Q39. When was the Indian Remote Sensing Satellite System (IRS) established?

  1. (a) 1959
  2. (b) 1983
  3. (c) 1972
  4. (d) 1988
Answer & solution

Answer: (d) 1988

Answer: Option 4 — 1988
The Indian Remote Sensing (IRS) satellite system began with IRS-1A, launched on 17 March 1988.
It was launched from Baikonur (then USSR) on a Soviet Vostok rocket.
Revision note — India's remote sensing satellites
• Bhaskara-I (1979) was India's first experimental earth-observation satellite; IRS-1A (1988) was the first operational one.
• The IRS system is one of the largest civilian remote sensing constellations in the world.
• Data is received and distributed by the National Remote Sensing Centre (NRSC), Hyderabad.
• Uses: crop estimation, forest cover, drought and flood monitoring, groundwater mapping, urban planning.
• Later series: Resourcesat, Cartosat (mapping), Oceansat (oceans), RISAT (radar imaging); now named EOS.
• IRS satellites are placed in Sun-synchronous polar orbit, mostly by PSLV.
Do not mix these up
• 1972 is when the Department of Space and Space Commission were set up; 1969 is ISRO's founding — not the IRS.
Also asked from this topic: the agency that manages satellite remote sensing for environmental study (ISRO, through NRSC); the orbit PSLV mainly uses (polar orbit).
Books and Authors · Modern Indian books and authors

Q40. The author of the famous novel 'Midnight's Children' is:

  1. (a) Salman Rushdie
  2. (b) Khushwant Singh
  3. (c) Ruskin Bond
  4. (d) Shashi Tharoor
Answer & solution

Answer: (a) Salman Rushdie

Answer: Option 1 — Salman Rushdie
Midnight's Children (1981) is Salman Rushdie's novel about Saleem Sinai, born at the midnight of India's independence.
It won the Booker Prize, 1981.
Revision note — Salman Rushdie and Indian Booker winners
• Midnight's Children uses magical realism; it was named the Booker of Bookers (1993) and Best of the Booker (2008).
• Other Rushdie books: Shame, The Satanic Verses, The Moor's Last Sigh, Shalimar the Clown, Joseph Anton (memoir).
• Booker winners of Indian origin: Arundhati Roy — The God of Small Things (1997); Kiran Desai — The Inheritance of Loss (2006); Aravind Adiga — The White Tiger (2008).
• Geetanjali Shree — Tomb of Sand — won the International Booker Prize, 2022.
Do not mix these up
• Khushwant Singh — Train to Pakistan; Ruskin Bond — The Room on the Roof, The Blue Umbrella; Shashi Tharoor — The Great Indian Novel, An Era of Darkness.
Also asked from this topic: the Rushdie book that won the 1981 Booker Prize (Midnight's Children); the author of Shalimar the Clown (Salman Rushdie); the author of Joseph Anton: A Memoir (Salman Rushdie).

Modern History (1)

Socio-Religious Reform Movements · Women reformers

Q41. Who among the following women started the Women's Indian Association in 1917?

  1. (a) Usha Mehta
  2. (b) Madam Bhikaji Cama
  3. (c) Annie Besant
  4. (d) Sarojini Naidu
Answer & solution

Answer: (c) Annie Besant

Answer: Option 3 — Annie Besant
The Women's Indian Association (WIA) was founded in 1917 at Adyar, Madras by Annie Besant, with Margaret Cousins and Dorothy Jinarajadasa.
It worked for women's education and women's right to vote.
Revision note — Annie Besant
• Irish-born Theosophist; President of the Theosophical Society (Adyar) from 1907.
• Helped found the Central Hindu College, Banaras (1898), later part of BHU.
• Started the Home Rule League at Madras in September 1916; Tilak's league began at Belgaum in April 1916.
• First woman President of the INC — Calcutta session, 1917.
• Ran the newspapers New India and Commonweal.
• Margaret Cousins later helped start the All India Women's Conference (1927).
Do not mix these up
• Annie Besant vs Sarojini Naidu — Besant was the first woman INC President (1917); Naidu was the first Indian woman INC President (1925, Kanpur).
• Bhikaji Cama hoisted an Indian flag at Stuttgart (1907); Usha Mehta ran the secret Congress Radio in 1942.
Also asked from this topic: the first woman President of the INC (Annie Besant); the founder of the Home Rule League at Madras (Annie Besant); the woman who hoisted India's flag at Stuttgart in 1907 (Bhikaji Cama).

Geography (1)

India - Location, Physiography and Neighbours · Thar Desert

Q42. The climate of the Thar desert is best described as ________.

  1. (a) humid subtropical
  2. (b) arid
  3. (c) tropical rainforest
  4. (d) temperate
Answer & solution

Answer: (b) arid

Answer: Option 2 — arid
The Thar (Great Indian) Desert gets very little rain — under 150 mm a year in its western part — with high evaporation and extreme temperatures.
Such a dry climate is called arid.
Revision note — The Thar Desert
• Lies west of the Aravalli hills, mostly in Rajasthan; arid and semi-arid climate.
• Very hot days, cold nights; large daily range of temperature.
• Land of sand dunes, especially crescent-shaped barchans.
• Luni is the only large river; most streams vanish into the sand (inland drainage).
• Salt lakes called playas (e.g. Sambhar); vegetation is thorny and xerophytic.
• Marine deposits and wood fossils show it was under the sea in the Mesozoic era.
• The Indira Gandhi Canal (from Harike barrage, Punjab) irrigates its western part.
Also asked from this topic: the main river of the Thar Desert (Luni); the local name of its brackish lakes (playas); where the Indira Gandhi Canal begins (Harike barrage, Punjab).
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