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RRB JE CBT-1 2024-25 16 December 2024 Shift 3 GK Questions – with answers & solutions

All 44 GK / GS questions asked in RRB JE CBT-1 2024-25 on 16 December 2024 Shift 3, with correct answers and short solutions, subject-wise: Chemistry, Polity, Current Affairs, Biology, Physics, Economics.

📚 44 questions🗓️ 16 December 2024⏰ Shift 3
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Subjects: Chemistry (10) · Polity (3) · Current Affairs (5) · Biology (10) · Physics (10) · Economics (1) · Modern History (1) · Static GK (2) · Ancient History (1) · Geography (1)

Chemistry (10)

Chemical Reactions and Equations · Combination reactions

Q1. Which of the following best describes a combination reaction?

  1. (a) A reaction where a product releases gas
  2. (b) Ions exchange between two compounds
  3. (c) Two elements combine to form a compound
  4. (d) A compound breaks down into simpler substances
Answer & solution

Answer: (c) Two elements combine to form a compound

Answer: Option 3 — Two elements combine to form a compound
In a combination reaction two or more reactants join to give a single product, e.g. C + O_(2) → CO_(2).
Revision note — Types of chemical reactions
• Combination: A + B → AB — CaO + H_(2)O → Ca(OH)_(2) (quicklime + water → slaked lime, with heat).
• Decomposition: AB → A + B — the reverse of combination; needs heat, light or electricity.
• Displacement: a more reactive metal pushes out a less reactive one — Fe + CuSO_(4) → FeSO_(4) + Cu.
• Double displacement: ions are exchanged, often giving a precipitate — Na_(2)SO_(4) + BaCl_(2) → BaSO_(4)↓ + 2NaCl.
• Burning of coal and formation of water from H_(2) and O_(2) are combination reactions.
• Most combination reactions are exothermic (release heat).
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: what identifies a combination reaction (only one new substance is produced); the type of CaO + H_(2)O → Ca(OH)_(2) + heat (combination).
Chemical Reactions and Equations · Writing and balancing chemical equations

Q2. Which of the following chemical equations is balanced?

  1. (a) H₂ + O₂ → H₂O
  2. (b) H₂ + 2O₂ → 2H₂O
  3. (c) H₂O + O₂ → H₂O₂
  4. (d) 2H₂ + O₂ → 2H₂O
Answer & solution

Answer: (d) 2H₂ + O₂ → 2H₂O

Answer: Option 4 — 2H₂ + O₂ → 2H₂O
A balanced equation has the same number of atoms of each element on both sides.
Left: 4 H, 2 O; right: 2H_(2)O = 4 H, 2 O — both match.
Revision note — Balancing chemical equations
• Balancing follows the law of conservation of mass (Lavoisier): atoms are neither created nor destroyed.
• Change only the coefficients in front of formulae — never the subscripts (H_(2)O cannot become H_(2)O_(2)).
• Method: balance the element in the largest formula first, leave H and O for the end (hit-and-trial method).
• An equation before balancing is a skeletal equation.
• State symbols: (s) solid, (l) liquid, (g) gas, (aq) aqueous solution.
• Burning hydrogen in oxygen is a combination reaction and is exothermic.
Do not mix these up
• Balanced vs correct — balancing only matches atom counts; the formulae themselves must be the right reactants and products, and they are never altered to force a balance.
Also asked from this topic: a reaction that breaks the law of conservation of mass as written (2Mg + O_(2) → MgO, correct form 2Mg + O_(2) → 2MgO).
Chemical Reactions and Equations · Oxidation, reduction and redox reactions

Q3. In the reaction MnO_(2) + 4HCl → MnCl_(2) + 2H_(2)O + Cl_(2), what is being reduced?

  1. (a) Chlorine (Cl)
  2. (b) Manganese (Mn)
  3. (c) Hydrogen (H)
  4. (d) Oxygen (O)
Answer & solution

Answer: (b) Manganese (Mn)

Answer: Option 2 — Manganese (Mn)
MnO_(2) loses its oxygen and becomes MnCl_(2), so it is reduced.
In oxidation-number terms, Mn falls from +4 in MnO_(2) to +2 in MnCl_(2) — a gain of electrons.
Revision note — Oxidation and reduction (NCERT Class 10)
• Oxidation = gain of oxygen or loss of hydrogen (or loss of electrons).
• Reduction = loss of oxygen or gain of hydrogen (or gain of electrons).
• In this reaction HCl is oxidised to Cl_(2) (it loses hydrogen; Cl goes from −1 to 0).
• The substance that is reduced is the oxidising agent — here MnO_(2); the substance oxidised is the reducing agent — here HCl.
• A reaction in which one substance is oxidised and another reduced is a redox reaction.
• Another NCERT example: CuO + H_(2) → Cu + H_(2)O — CuO is reduced, H_(2) is oxidised.
Do not mix these up
• Reduced vs reducing agent — MnO_(2) is reduced but is the oxidising agent; HCl is oxidised but is the reducing agent.
Also asked from this topic: the substance oxidised in MnO_(2) + 4HCl → MnCl_(2) + 2H_(2)O + Cl_(2) (HCl); why MnO_(2) is said to be reduced (it loses oxygen).
Metals and Non-metals · Corrosion and its prevention (galvanisation, etc.)

Q4. Which of the following metals is least likely to corrode in moist air?

  1. (a) Iron
  2. (b) Zinc
  3. (c) Magnesium
  4. (d) Copper
Answer & solution

Answer: (d) Copper

Answer: Option 4 — Copper
Corrosion is faster for more reactive metals.
Of the four, copper is lowest in the reactivity series (Mg > Zn > Fe > Cu), so it corrodes least.
Revision note — Corrosion of metals
• Corrosion — slow eating away of a metal by air, moisture or chemicals on its surface.
• Iron → rust, a reddish-brown hydrated iron(III) oxide, Fe_(2)O_(3)·xH_(2)O; rusting needs both air (oxygen) and water.
• Copper → slowly loses its shine and gets a green coat of basic copper carbonate (moist CO_(2) in air).
• Silver → turns black (silver sulphide, from sulphur in air).
• Prevention: painting, oiling, greasing, galvanising, chrome-plating, anodising and making alloys.
• Galvanisation — coating iron with zinc; zinc, being more reactive, corrodes first and protects the iron.
• Gold and platinum hardly corrode at all — they are the least reactive metals.
Do not mix these up
• Zinc vs copper — zinc is more reactive than iron and is used to protect iron; copper is less reactive and corrodes only slowly on its own.
Also asked from this topic: the colour of the layer formed on copper in moist air (green); the chemical in rust (hydrated iron(III) oxide, Fe_(2)O_(3)·xH_(2)O).
Metals and Non-metals · Ionic compounds and their properties

Q5. When an atom of sodium reacts with an atom of chlorine to form sodium chloride, each sodium atom:

  1. (a) gains one proton
  2. (b) loses one electron
  3. (c) gains one electron
  4. (d) loses one proton
Answer & solution

Answer: (b) loses one electron

Answer: Option 2 — loses one electron
Sodium has the configuration 2, 8, 1 — it gives up its single outer electron to become Na^(+) (2, 8).
Chlorine (2, 8, 7) takes that electron and becomes Cl^(−) (2, 8, 8).
Revision note — Formation of ionic compounds
• An ionic (electrovalent) bond forms by transfer of electrons from a metal to a non-metal.
• The metal forms a cation (positive ion); the non-metal forms an anion (negative ion).
• Both ions reach a stable octet (noble-gas configuration): Na^(+) like neon, Cl^(−) like argon.
• The ions are held by strong electrostatic attraction.
• Ionic compounds are hard solids with high melting and boiling points, dissolve in water, and conduct electricity only when molten or in solution.
• Protons never move in a chemical reaction — only electrons are gained, lost or shared.
Do not mix these up
• Ionic vs covalent bond — ionic bonds transfer electrons (NaCl, MgCl_(2)); covalent bonds share electron pairs (H_(2)O, CO_(2), NH_(3)).
Also asked from this topic: a compound formed by ionic bonding (NaCl); the bond between a metal and a non-metal (ionic bond).
Acids, Bases and Salts · Common salts - preparation and uses (baking soda, washing soda, bleaching powder, plaster of Paris)

Q6. Which of the following reactions leads to the production of bleaching powder?

  1. (a) CaO + H_(2)O → Ca(OH)_(2)
  2. (b) Ca(OH)_(2) + Cl_(2) → CaOCl_(2) + H_(2)O
  3. (c) Ca(OH)_(2) + CO_(2) → CaCO_(3) + H_(2)O
  4. (d) CaCO_(3) + HCl → CaCl_(2) + CO_(2) + H_(2)O
Answer & solution

Answer: (b) Ca(OH)_(2) + Cl_(2) → CaOCl_(2) + H_(2)O

Answer: Option 2 — Ca(OH)_(2) + Cl_(2) → CaOCl_(2) + H_(2)O
Bleaching powder is made by passing chlorine gas over dry slaked lime [Ca(OH)_(2)].
The product is calcium oxychloride, CaOCl_(2) — bleaching powder.
Revision note — Bleaching powder and related salts
• Chlorine for it comes from the chlor-alkali process (electrolysis of brine).
• Bleaching powder releases chlorine, which does the bleaching and disinfecting.
• Uses: bleaching cotton, linen, wood pulp; disinfecting drinking water; oxidising agent in industry.
• CaO + H_(2)O → Ca(OH)_(2) — quicklime to slaked lime (exothermic combination).
• Ca(OH)_(2) + CO_(2) → CaCO_(3) + H_(2)O — lime water turns milky; test for CO_(2).
• Baking soda NaHCO_(3); washing soda Na_(2)CO_(3)·10H_(2)O; plaster of Paris CaSO_(4)·½H_(2)O.
Also asked from this topic: the gas responsible for bleaching action (chlorine); a use of bleaching powder besides bleaching (disinfecting drinking water); a use in industry (oxidising agent).
Acids, Bases and Salts · pH scale and its importance

Q7. Which of the following statements is true about the pH of a neutral solution at 25°C?

  1. (a) The pH is not equal to 7.
  2. (b) The pH is equal to 7.
  3. (c) The pH is greater than 7.
  4. (d) The pH is less than 7.
Answer & solution

Answer: (b) The pH is equal to 7.

Answer: Option 2 — The pH is equal to 7.
In a neutral solution the concentrations of H⁺ and OH⁻ ions are equal.
At 25°C each is 10^(−7) mol/L, so pH = 7.
Revision note — The pH scale
• pH = "potenz" (power) of hydrogen; the scale runs from 0 to 14 (proposed by S.P.L. Sørensen).
• pH < 7 — acidic; pH = 7 — neutral; pH > 7 — basic (alkaline).
• Lower pH = more H⁺ ions = stronger acid; each step of 1 is a 10-fold change in H⁺ concentration.
• Common values: gastric juice ≈ 1.2, lemon juice ≈ 2.2, pure water = 7, blood ≈ 7.4, milk of magnesia ≈ 10, NaOH ≈ 14.
• Our body works in the narrow range 7.0 – 7.8; tooth decay starts when mouth pH falls below 5.5.
• Universal indicator shows the full pH range by colour; litmus only tells acid or base.
Do not mix these up
• "Neutral" vs "pH 7" — pH 7 means neutral only at 25°C; at higher temperature pure water is still neutral but its pH is slightly below 7.
Also asked from this topic: the substance that is neutral on the pH scale (pure water); the most basic of lemon juice, soap solution, water and vinegar (soap solution, pH 9).
Carbon and its Compounds · Bonding in carbon and catenation

Q8. Covalent molecules have low melting and boiling point because:

  1. (a) they have weak intermolecular forces
  2. (b) they are generally gaseous in nature
  3. (c) they have strong bonds within the molecule
  4. (d) they have strong electrostatic intermolecular forces
Answer & solution

Answer: (a) they have weak intermolecular forces

Answer: Option 1 — they have weak intermolecular forces
Melting or boiling separates molecules from one another, not atoms inside a molecule.
In covalent compounds the forces between molecules are weak, so little heat is needed.
Revision note — Covalent compounds
• A covalent bond forms by sharing of electron pairs between two atoms (single, double or triple bond).
• The bonds within a molecule are strong; the forces between molecules are weak.
• Hence covalent compounds have low melting and boiling points and many are liquids or gases at room temperature.
• They are generally poor conductors of electricity — no ions are formed.
• Examples: CH_(4), H_(2)O, CO_(2), NH_(3), Cl_(2); carbon forms covalent bonds because it can neither gain nor lose 4 electrons easily.
• Ionic compounds (NaCl, MgCl_(2)) have high melting and boiling points due to strong electrostatic attraction between ions.
Do not mix these up
• Intramolecular vs intermolecular — the covalent bond inside the molecule is strong; the low melting point comes from the weak pull between molecules.
Also asked from this topic: why covalent compounds have low melting points (weak intermolecular forces); the property NOT typical of covalent carbon compounds (good conductors of electricity).
Chemical Reactions and Equations · Double displacement and precipitation reactions

Q9. Double displacement reactions usually occur in:

  1. (a) gaseous state
  2. (b) aqueous solution
  3. (c) solid state
  4. (d) all three states
Answer & solution

Answer: (b) aqueous solution

Answer: Option 2 — aqueous solution
A double displacement reaction is an exchange of ions between two compounds.
Ions move freely only when the salts are dissolved in water, so these reactions usually take place in aqueous solution.
Revision note — Double displacement reactions
• General form: AB + CD → AD + CB — the partners are swapped.
• Standard example: Na_(2)SO_(4)(aq) + BaCl_(2)(aq) → BaSO_(4)(s) + 2NaCl(aq).
• The white precipitate of barium sulphate marks it as a precipitation reaction.
• Other example: AgNO_(3) + NaCl → AgCl (white precipitate) + NaNO_(3).
• Neutralisation (acid + base → salt + water) is also a double displacement reaction.
• State symbols: (aq) dissolved in water, (s) solid, (l) liquid, (g) gas.
Do not mix these up
• Displacement vs double displacement — in displacement a more reactive element pushes out a less reactive one (Fe + CuSO_(4)); in double displacement two compounds exchange ions.
Also asked from this topic: the white product of barium chloride + sodium sulphate (barium sulphate precipitate); the main feature of a double displacement reaction (exchange of ions between reactants).
Carbon and its Compounds · Hydrocarbons - alkanes, alkenes, alkynes

Q10. Which of the following is the correct formula for the first member of the alkene series?

  1. (a) C₄H₈
  2. (b) C₂H₄
  3. (c) C₃H₆
  4. (d) C₅H₁₀
Answer & solution

Answer: (b) C₂H₄

Answer: Option 2 — C₂H₄
Alkenes have general formula C_(n)H_(2n) and need a C=C double bond, so the smallest has n = 2.
n = 2 ⇒ C_(2)H_(4), ethene (CH_(2)=CH_(2)).
Revision note — Alkanes, alkenes and alkynes
• Alkanes — C_(n)H_(2n+2), only single bonds, saturated; first member methane CH_(4).
• Alkenes — C_(n)H_(2n), one C=C double bond, unsaturated; ethene C_(2)H_(4), propene C_(3)H_(6), butene C_(4)H_(8).
• Alkynes — C_(n)H_(2n−2), one C≡C triple bond; first member ethyne (acetylene) C_(2)H_(2).
• Successive members of a homologous series differ by –CH_(2)– (14 u).
• Unsaturated hydrocarbons give addition reactions — e.g. hydrogenation of vegetable oils with a nickel catalyst.
• Ethene decolourises bromine water — the test for unsaturation.
Do not mix these up
• C_(3)H_(6) — it fits C_(n)H_(2n) but it is propene (second alkene); as a ring it is cyclopropane, a saturated compound.
Also asked from this topic: the general formula for alkanes (C_(n)H_(2n+2)); the hydrocarbon that most readily gives addition reactions (ethene).

Polity (3)

Parliament · Membership, qualifications and disqualifications

Q11. Which of the following is related to Article 84 of the Constitution?

  1. (a) Annual Financial Statement
  2. (b) Disqualification for membership
  3. (c) Qualification for membership of Parliament
  4. (d) Ordinance making Power of President
Answer & solution

Answer: (c) Qualification for membership of Parliament

Answer: Option 3 — Qualification for membership of Parliament
Article 84 lays down who can become a Member of Parliament.
Revision note — Membership of Parliament
• Art 84: must be a citizen of India, take an oath as per the Third Schedule, and be at least 25 years (Lok Sabha) or 30 years (Rajya Sabha) old.
• Other qualifications are set by Parliament through the Representation of the People Act, 1951.
• Art 102: disqualifications for membership; Art 101: vacation of seats.
• Art 112: Annual Financial Statement (the Budget).
• Art 123: Ordinance-making power of the President (Art 213 for the Governor).
• Tenth Schedule (added by the 52nd Amendment, 1985) — disqualification on grounds of defection.
Do not mix these up
• Article 84 vs Article 102 — 84 says who can be a member; 102 says who cannot.
Also asked from this topic: the minimum age to become a Lok Sabha member under Article 84 (25 years); the minimum age for Rajya Sabha membership (30 years).
Union, Territory and Citizenship · OCI, NRI and CAA

Q12. According to the Citizenship Amendment Act of 2019, individuals who entered India on or before _______ and belong to the Hindu, Sikh, Buddhist, Jain, Parsi or Christian community from Pakistan, Afghanistan or Bangladesh are eligible for citizenship.

  1. (a) 31 December 2014
  2. (b) 31 December 2015
  3. (c) 31 December 2017
  4. (d) 31 December 2016
Answer & solution

Answer: (a) 31 December 2014

Answer: Option 1 — 31 December 2014
The Citizenship (Amendment) Act, 2019 covers Hindu, Sikh, Buddhist, Jain, Parsi and Christian migrants from Pakistan, Afghanistan and Bangladesh who entered India on or before 31 December 2014.
Revision note — Citizenship (Amendment) Act, 2019
• It amends the Citizenship Act, 1955; Parliament's power to make citizenship law comes from Article 11.
• Residence needed for naturalisation cut from 11 years to 5 years for these communities.
• Came into force on 10 January 2020; its Rules were notified on 11 March 2024.
• Does not apply to Sixth Schedule tribal areas of Assam, Meghalaya, Mizoram and Tripura, or to Inner Line Permit areas.
• Constitutional provisions on citizenship: Articles 5–11, Part II.
• Citizenship Act 1955 modes: birth, descent, registration, naturalisation, incorporation of territory.
Also asked from this topic: the three countries covered by CAA 2019 (Afghanistan, Bangladesh, Pakistan); the areas it excludes (Sixth Schedule areas and ILP regions).
Parliament · Leader of Opposition and parliamentary terms

Q13. Who among the following is the leader of the house in the Lok Sabha?

  1. (a) Prime Minister
  2. (b) Opposition Leader
  3. (c) Lok Sabha Speaker
  4. (d) President of India
Answer & solution

Answer: (a) Prime Minister

Answer: Option 1 — Prime Minister
Under the Rules of Procedure of the Lok Sabha, the Prime Minister, if a member of the Lok Sabha, is the Leader of the House.
If the PM is not a Lok Sabha member, he nominates a minister who is.
Revision note — Leaders in Parliament
• The Leader of the House arranges government business and the order of work in the House.
• Rajya Sabha: the Leader of the House is a minister nominated by the PM (Dec 2024: J. P. Nadda).
• Leader of Opposition (LoP) — leader of the largest opposition party with at least 10% of the seats (55 in Lok Sabha).
• LoP gets statutory recognition under the Salary and Allowances of Leaders of Opposition in Parliament Act, 1977, with Cabinet-minister rank.
• The LoP post in Lok Sabha was vacant 2014–2024; Rahul Gandhi became LoP in June 2024.
• The Speaker presides over the Lok Sabha; the Vice-President is ex-officio Chairman of the Rajya Sabha.
Do not mix these up
• Leader of the House vs Speaker — the Leader of the House leads the government side; the Speaker is the neutral presiding officer.
Also asked from this topic: the minimum share of seats needed for a party's leader to be recognised as LoP (10% — 55 seats); who appoints the Prime Minister (the President).

Current Affairs (5)

Sports - Current · Olympics, Asian Games and Commonwealth Games - current

Q14. Who among the following secured a gold medal for India at the Paris Paralympics 2024?

  1. (a) Hokato Hotozhe Sema
  2. (b) Pranav Soorma
  3. (c) Navdeep Singh
  4. (d) Sachin Khilari
Answer & solution

Answer: (c) Navdeep Singh

Answer: Option 3 — Navdeep Singh
Navdeep Singh won gold in the men's javelin throw F41 at the Paris 2024 Paralympics with a throw of 47.32 m; his silver was upgraded after the original winner was disqualified.
Revision note — India at the Paris 2024 Paralympics
• India won 29 medals — 7 gold, 9 silver, 13 bronze — its best ever, finishing 18th.
• Gold: Avani Lekhara (10 m air rifle SH1), Nitesh Kumar (badminton SL3), Sumit Antil (javelin F64), Harvinder Singh (archery).
• More gold: Dharambir (club throw F51), Praveen Kumar (high jump T64), Navdeep Singh (javelin F41).
• Sachin Khilari — silver, shot put F46; Pranav Soorma — silver, club throw F51.
• Hokato Hotozhe Sema — bronze, shot put F57.
• Flag-bearers at the opening: Sumit Antil and Bhagyashri Jadhav.
• The Games were held from 28 August to 8 September 2024.
Also asked from this topic: India's first Paralympic archery gold (Harvinder Singh); India's first Paralympic judo medal (Kapil Parmar, bronze).
Science, Technology and Space - Current · Space sector policy, industry and start-ups - current

Q15. Space Kidz India has launched the ShakthiSAT mission to train _________ girls aged 14-18 from 108 countries in space technology, aiming for a satellite launch under ISRO's Chandrayaan-4 mission in 2026.

  1. (a) 7500
  2. (b) 5000
  3. (c) 10,000
  4. (d) 12,000
Answer & solution

Answer: (d) 12,000

Answer: Option 4 — 12,000
Space Kidz India launched the ShakthiSAT mission in 2024 to train 12,000 girls aged 14–18 from 108 countries in space technology, aiming to build a satellite for a lunar mission.
Revision note — ShakthiSAT and student space missions
• Space Kidz India is a Chennai-based space-education start-up led by Srimathy Kesan.
• Its earlier student satellites include Kalamsat-V2 (2019, launched on PSLV-C44) and AzaadiSAT (2022, SSLV-D1, built by 750 schoolgirls).
• Chandrayaan-4 is ISRO's planned lunar sample-return mission, to be launched in two LVM3 flights.
• The mission promotes girls in STEM and global cooperation in space education.
Also asked from this topic: the number of launches planned for Chandrayaan-4 (two).
International Affairs and Summits · Summits and conferences

Q16. What was the venue of the 57^(th) ASEAN Foreign Ministers’ Meeting?

  1. (a) Naypyidaw, Myanmar
  2. (b) Vientiane, Lao People's Democratic Republic
  3. (c) Jakarta, Indonesia
  4. (d) Kuala Lumpur, Malaysia
Answer & solution

Answer: (b) Vientiane, Lao People's Democratic Republic

Answer: Option 2 — Vientiane, Lao People's Democratic Republic
The 57th ASEAN Foreign Ministers' Meeting was held at Vientiane, Laos, in July 2024, as Lao PDR held the ASEAN Chair for 2024.
Revision note — ASEAN
• ASEAN — Association of Southeast Asian Nations, formed on 8 August 1967 by the Bangkok Declaration.
• Founding members: Indonesia, Malaysia, Philippines, Singapore, Thailand.
• 10 members: the five founders + Brunei, Vietnam, Laos, Myanmar, Cambodia; Timor-Leste was admitted in principle in 2022.
• Secretariat: Jakarta, Indonesia.
• Theme of Laos's 2024 chairship: "ASEAN: Enhancing Connectivity and Resilience".
• India is a dialogue partner; its Act East Policy (2014) has ASEAN at its centre. External Affairs Minister S. Jaishankar attended the 2024 meeting.
• As of 2026: Timor-Leste became ASEAN's 11th member in October 2025.
Do not mix these up
• Vientiane vs Jakarta — Vientiane hosted the 2024 meetings as chair; Jakarta is the permanent ASEAN Secretariat.
Also asked from this topic: the only landlocked country in Southeast Asia (Laos); a country that is not an ASEAN member (Pakistan; India is only a dialogue partner).
National Affairs and Government Initiatives · New government schemes and missions

Q17. Which of the following statements is/are correct about the PM Vishwakarma Yojana?1) The PM Vishwakarma Yojana was launched by the Hon'ble Prime Minister on 17 September 2023.2) Scheme aims to provide end-to-end support to artisans and craftspeople who work with their hands and tools.3) The Scheme components include recognition through PM Vishwakarma Certificate and ID Card, Skill Upgradation, Toolkit Incentive, Credit Support, Incentive for Digital Transactions, and Marketing Support.

  1. (a) 1, 2 and 3
  2. (b) 3 only
  3. (c) 2 only
  4. (d) 1 only
Answer & solution

Answer: (a) 1, 2 and 3

Answer: Option 1 — 1, 2 and 3
All three statements are correct.
PM Vishwakarma was launched by the Prime Minister on 17 September 2023 (Vishwakarma Jayanti).
It gives end-to-end support to artisans and craftspeople who work with their hands and tools.
Revision note — PM Vishwakarma scheme
• Nodal ministry: Ministry of Micro, Small and Medium Enterprises (MSME); a Central Sector scheme.
• Covers 18 traditional trades — carpenter, blacksmith, potter, goldsmith, cobbler, barber, tailor, mason and others.
• Recognition through the PM Vishwakarma Certificate and ID Card.
• Skill upgradation with a stipend of ₹500 per day, and a toolkit incentive of up to ₹15,000.
• Collateral-free credit of up to ₹3 lakh in two tranches (₹1 lakh and ₹2 lakh) at a concessional 5% interest.
• Also gives an incentive for digital transactions and marketing support.
• Eligible artisans must be at least 18 years old.
Also asked from this topic: the ministry that runs PM Vishwakarma (MSME); the number of trades covered (18); the group it supports (traditional artisans and craftspeople).
Environment and Climate - Current · Environmental rules, campaigns and summits - current

Q18. Where was the Swachh Vayu Diwas celebrated in India to combat air pollution in 2024?

  1. (a) Chandigarh
  2. (b) Indore
  3. (c) Bhopal
  4. (d) Jaipur
Answer & solution

Answer: (d) Jaipur

Answer: Option 4 — Jaipur
The Ministry of Environment, Forest and Climate Change celebrated Swachh Vayu Diwas 2024 in Jaipur, Rajasthan on 7 September 2024.
It marks the UN's International Day of Clean Air for Blue Skies.
Revision note — Swachh Vayu Diwas and NCAP
• International Day of Clean Air for Blue Skies — 7 September, declared by the UN General Assembly in 2019; first observed in 2020.
• India observes it as Swachh Vayu Diwas; the 2024 event was held in Jaipur under Union Environment Minister Bhupender Yadav.
• Swachh Vayu Survekshan 2024 awards were given there — top cities: Surat (population over 10 lakh), Firozabad (3–10 lakh), Raebareli (under 3 lakh).
• The survey ranks cities under the National Clean Air Programme (NCAP), launched in January 2019.
• NCAP covers 131 non-attainment cities; its revised target is a 40% cut in PM_(10) (or meeting national standards) by 2025–26 over 2017–18 levels.
• PRANA is the online portal that tracks NCAP progress.
Also asked from this topic: NCAP's original target for particulate pollution by 2024–25 over 2017–18 (20–30% reduction).

Biology (10)

Reproduction · Asexual reproduction (fission, budding, fragmentation, spores)

Q19. Which of the following is true regarding the bud development process in Hydra?

  1. (a) Cell divisions at one site
  2. (b) Splitting of nucleus
  3. (c) Splitting of cytoplasm
  4. (d) Formation of spore
Answer & solution

Answer: (a) Cell divisions at one site

Answer: Option 1 — Cell divisions at one site
In Hydra, a bud grows as an outgrowth because of repeated cell division at one specific site; it matures into a tiny Hydra and detaches from the parent.
Revision note — Modes of asexual reproduction
• Budding: Hydra (regenerative cells) and yeast.
• Binary fission: Amoeba (any plane), Leishmania (a definite plane, due to its flagellum).
• Multiple fission: Plasmodium (malarial parasite) — many daughter cells at once.
• Fragmentation: Spirogyra — each fragment grows into a new filament.
• Regeneration: Planaria and Hydra — a cut piece rebuilds the whole body.
• Spore formation: Rhizopus (bread mould) — spores in sporangia.
• Asexual reproduction has one parent and no gametes, so offspring are near-copies of the parent.
Do not mix these up
• Budding vs regeneration in Hydra — budding is normal reproduction from one site; regeneration is rebuilding from a cut piece.
Also asked from this topic: what Amoeba, yeast and Hydra show about asexual reproduction (it occurs without fusion of gametes).
Reproduction · Flower structure and sexual reproduction in plants

Q20. What is the role of the stigma in the process of fertilisation?

  1. (a) Developing into a seed
  2. (b) Producing pollen
  3. (c) Fusing with the egg cell
  4. (d) Serving as the site where pollen lands
Answer & solution

Answer: (d) Serving as the site where pollen lands

Answer: Option 4 — Serving as the site where pollen lands
The stigma is the sticky tip of the carpel (pistil).
Pollen grains land and stick here; a pollen tube then grows down the style to the ovule in the ovary.
Revision note — Parts of a flower and fertilisation
• Stamen (male) = anther + filament; the anther makes pollen grains.
• Carpel / pistil (female) = stigma + style + ovary; the ovary holds ovules, each with an egg cell.
• Pollination — transfer of pollen from anther to stigma: self-pollination (same flower) or cross-pollination (another flower, by wind, water, insects).
• Fertilisation — the male germ cell fuses with the egg cell inside the ovule, forming the zygote.
• After fertilisation: ovule → seed, ovary → fruit, zygote → embryo; petals, sepals, stamens, style and stigma wither.
• Bisexual flowers have both stamens and carpels (hibiscus, mustard); unisexual flowers have one (papaya, watermelon).
Do not mix these up
• Stigma vs style — the stigma receives pollen; the style is the stalk the pollen tube grows through.
• Pollination vs fertilisation — pollination is the transfer of pollen; fertilisation is the fusion of gametes.
Also asked from this topic: the female reproductive part of a flower (gynoecium / pistil); what fertilisation is, as against pollination (fusion of gametes).
Reproduction · Fertilisation, embryo development and pregnancy

Q21. Which of the following helps a developing embryo to expel waste products in case of humans?

  1. (a) Placenta
  2. (b) Ovary
  3. (c) Cervix
  4. (d) Oviduct
Answer & solution

Answer: (a) Placenta

Answer: Option 1 — Placenta
The placenta is a disc-shaped tissue embedded in the uterine wall that links the embryo to the mother.
Wastes made by the embryo pass through it into the mother's blood for removal.
Revision note — Placenta and development of the embryo
• Fertilisation takes place in the oviduct (fallopian tube); the zygote then implants in the uterus lining.
• The placenta has villi on the embryo's side, giving a large surface area for exchange.
• Mother → embryo: glucose, oxygen and other nutrients.
• Embryo → mother: carbon dioxide and other wastes.
• The embryo's blood and the mother's blood do not mix — exchange is across the placental tissue.
• The placenta also secretes hormones that maintain pregnancy.
• Development takes about 9 months (about 40 weeks); zygote → embryo → foetus.
Do not mix these up
• Placenta vs oviduct — the oviduct is where fertilisation happens; the placenta feeds the embryo and removes its wastes.
Also asked from this topic: the immunity a foetus gets from maternal antibodies through the placenta (passive natural immunity); the order of development (zygote → embryo → foetus).
Reproduction · Reproduction in animals

Q22. Which of the following is called a motile germ cell?

  1. (a) Male gamete
  2. (b) Embryo
  3. (c) Zygote
  4. (d) Female gamete
Answer & solution

Answer: (a) Male gamete

Answer: Option 1 — Male gamete
The male germ cell (sperm) is small and motile — it has a long tail to swim towards the egg.
The female germ cell (egg) is larger, stores food, and does not move.
Revision note — Germ cells (gametes)
• Gametes are reproductive cells formed by meiosis; each has half the chromosomes (in humans 23).
• Sperm are made in the testes; the egg (ovum) is made in the ovaries.
• Sperm have a head (nucleus), a middle piece (mitochondria for energy) and a tail for movement.
• Fusion of male and female gametes = fertilisation; the product is the zygote (46 chromosomes in humans).
• In humans fertilisation takes place in the oviduct (fallopian tube).
• In flowering plants the male germ cell is carried in the pollen grain and reaches the ovule through the pollen tube.
Do not mix these up
• Gamete vs zygote — the gamete is a single sex cell; the zygote is the fused cell formed after fertilisation. The embryo develops from the zygote.
Also asked from this topic: the name for reproductive cells such as sperm and eggs (gametes); fertilisation as against pollination (fusion of gametes); the organ that produces eggs (ovaries).
Heredity and Evolution · Mendel's laws and experiments

Q23. The knowledge of which two subjects played key role in formulating laws of Inheritance?

  1. (a) Maths and Science
  2. (b) Maths and History
  3. (c) Philosophy and Science
  4. (d) Geography and Philosophy
Answer & solution

Answer: (a) Maths and Science

Answer: Option 1 — Maths and Science
Gregor Johann Mendel used his knowledge of science (biology) and mathematics (statistics) to form the laws of inheritance.
He counted the offspring of each type and found fixed ratios such as 3 : 1 and 9 : 3 : 3 : 1.
Revision note — Mendel and the laws of inheritance
• Mendel (1822–1884) is the Father of Genetics; he worked on the garden pea (Pisum sativum).
• He studied seven pairs of contrasting traits — tall/dwarf, round/wrinkled seed, yellow/green seed and others.
• Monohybrid cross (tall × dwarf): F_(1) all tall; F_(2) ratio 3 : 1 (phenotype), 1 : 2 : 1 (genotype).
• Dihybrid cross: F_(2) phenotypic ratio 9 : 3 : 3 : 1.
• Law of dominance; law of segregation (the two alleles separate during gamete formation); law of independent assortment.
• TT and Tt plants are tall; only tt plants are dwarf — tallness is dominant.
Also asked from this topic: the law that explains separation of alleles during gamete formation (law of segregation); the kind of trait tallness is in pea plants (dominant); the genotype of a short pea plant (tt).
Reproduction · Seed, fruit and germination

Q24. After fertilisation, the zygote divides multiple times to form which structure within the ovule?

  1. (a) Seed
  2. (b) Embryo
  3. (c) Fruit
  4. (d) Style
Answer & solution

Answer: (b) Embryo

Answer: Option 2 — Embryo
The zygote divides many times by mitosis to form the embryo inside the ovule.
The ovule as a whole later becomes the seed; the embryo is the part inside it.
Revision note — Changes in a flower after fertilisation
• Zygote → embryo
• Ovule → seed (its coat hardens into the seed coat)
• Ovary → fruit; the ovary wall becomes the pericarp
• Petals, sepals, stamens, style and stigma usually wither and fall off.
• The seed holds the future plant (embryo); the embryo has a plumule (future shoot), a radicle (future root) and cotyledons (stored food).
• The seed grows into a new plant under suitable conditions — germination.
Do not mix these up
• Embryo vs seed — the embryo develops from the zygote; the seed develops from the ovule and contains the embryo.
Also asked from this topic: the order of development in human gestation (zygote → embryo → foetus); the process that forms the zygote (fusion of gametes, fertilisation).
Reproduction · Asexual reproduction (fission, budding, fragmentation, spores)

Q25. What is the thread-like structure in Rhizopus?

  1. (a) Blobs
  2. (b) Spores
  3. (c) Hyphae
  4. (d) Sporangia
Answer & solution

Answer: (c) Hyphae

Answer: Option 3 — Hyphae
The body of Rhizopus (bread mould) is made of fine thread-like filaments called hyphae.
The knob-like structures on the erect hyphae are sporangia, which hold the spores.
Revision note — Spore formation in Rhizopus
• Rhizopus is a fungus that grows on moist bread as a white-grey cotton-like mass.
• Hyphae — thread-like filaments; a mass of hyphae is a mycelium.
• Sporangia — round blobs at the tips of erect hyphae; each contains many spores.
• Spores have a thick protective wall; they survive until they reach a moist surface and then germinate.
• Spore formation is a type of asexual reproduction (single parent, no gametes).
• Other asexual methods: binary fission (Amoeba), budding (Hydra, yeast), fragmentation (Spirogyra), regeneration (Planaria).
Do not mix these up
• Hyphae vs sporangia — hyphae are the threads; sporangia are the spore cases at their tips.
Also asked from this topic: how bread moulds feed (digest food outside the body, then absorb it); best conditions for fungal growth (warm and moist).
Reproduction · Seed, fruit and germination

Q26. What is the final product of sexual reproduction in plants?

  1. (a) Flowers
  2. (b) Leaves
  3. (c) Fruits
  4. (d) Seeds
Answer & solution

Answer: (d) Seeds

Answer: Option 4 — Seeds
Sexual reproduction ends with the zygote, which grows into the embryo.
The embryo is packed inside the seed (from the ovule) — the seed is the new generation that grows into a plant.
Revision note — Changes after fertilisation in a flower
• Zygote → embryo; ovule → seed; ovary → fruit; ovary wall → pericarp.
• Sepals, petals, stamens, style and stigma usually wither and fall off.
• A seed has an embryo (plumule + radicle), cotyledons (stored food) and a protective seed coat.
• Plumule grows into the shoot; radicle grows into the root.
• Germination needs water, air (oxygen) and a suitable temperature — not light.
• The fruit protects the seeds and helps in their dispersal.
Do not mix these up
• Seed vs fruit — the seed carries the embryo (next generation); the fruit is only the ripened ovary that holds the seeds.
Also asked from this topic: the part of a plant primarily responsible for sexual reproduction in angiosperms (flower).
Reproduction · Reproductive health and contraception

Q27. Why might surgical family planning methods be risky if not done correctly?

  1. (a) They may cause hormonal side effects.
  2. (b) They might prevent ovulation.
  3. (c) They can increase fertility.
  4. (d) They can lead to infections or complications.
Answer & solution

Answer: (d) They can lead to infections or complications.

Answer: Option 4 — They can lead to infections or complications.
Surgical methods block the vas deferens or the fallopian tube by an operation.
NCERT notes they are safe in the long run but can cause infection and other problems if not done properly.
Revision note — Methods of contraception
• Barrier methods — condoms, diaphragm; they block sperm and also protect against STDs.
• Hormonal (chemical) methods — oral pills change the hormonal balance so that eggs are not released; may have side effects.
• Intrauterine devices — Copper-T or loop placed in the uterus; can cause side effects due to irritation of the uterus.
• Surgical methods — vasectomy (males: vas deferens blocked, sperm transfer stopped) and tubectomy (females: fallopian tube blocked, egg does not reach the uterus).
• Surgical methods are permanent in practice and give no protection against STDs.
• Birth control helps keep the population in check; female foeticide is prohibited and the sex-selective use of prenatal tests is banned by law.
Do not mix these up
• Pills vs surgery — hormonal side effects and stopping ovulation belong to oral pills; the risk with surgery is infection or complications from a badly done operation.
Also asked from this topic: a limitation of permanent surgical contraception (does not prevent infections).
Reproduction · Asexual reproduction (fission, budding, fragmentation, spores)

Q28. In plants, spore formation is a mode of reproduction that involves the production of spores. Which of the following statements about spore formation is true?

  1. (a) Spores are produced by non-flowering plants like ferns and mosses, and they grow into new plants.
  2. (b) Spores are a form of vegetative propagation in angiosperms only.
  3. (c) Spores are produced by flowers, and they grow into seeds.
  4. (d) Spores are formed through sexual reproduction in plants.
Answer & solution

Answer: (a) Spores are produced by non-flowering plants like ferns and mosses, and they grow into new plants.

Answer: Option 1 — Spores are produced by non-flowering plants like ferns and mosses, and they grow into new plants.
Spore formation is an asexual method.
Non-flowering plants such as ferns (pteridophytes) and mosses (bryophytes), and fungi, release spores that germinate directly into new individuals.
Revision note — Spore formation
• Spores are formed in sporangia — the knob-like structures on the hyphae of Rhizopus (bread mould).
• Each spore has a thick protective wall that lets it survive unfavourable conditions until it finds a moist surface.
• Spores are light and spread by air, so the organism reaches new places.
• Ferns carry spore sacs (sori) on the underside of their leaves; mosses bear spores in a capsule.
• Other asexual methods: fission (Amoeba, Leishmania, Plasmodium), budding (Hydra, yeast), fragmentation (Spirogyra), regeneration (Planaria).
• Flowering plants reproduce sexually through seeds; spores are not a form of vegetative propagation.
Do not mix these up
• Spore vs seed — a spore is a single cell formed asexually with no stored food or embryo; a seed has an embryo and stored food and comes from sexual reproduction.
Also asked from this topic: the plant group with vascular tissue but no seeds (Pteridophyta); what asexual reproduction in Amoeba, yeast and Hydra shows (it occurs without fusion of gametes).

Physics (10)

Light - Refraction and Lenses · Convex lens - image formation and uses

Q29. In the case of a thin lens, how are the centres of curvature typically positioned relative to the optical centre?

  1. (a) They are closer to the edge than to the optical centre.
  2. (b) They coincide with the optical centre.
  3. (c) They are equidistant from the optical centre.
  4. (d) They are located on the lens surface itself.
Answer & solution

Answer: (c) They are equidistant from the optical centre.

Answer: Option 3 — They are equidistant from the optical centre.
A thin lens with equally curved faces has its two centres of curvature, C_(1) and C_(2), on the principal axis, one on each side, at the same distance from the optical centre O.
Revision note — Spherical lens terms
• Centre of curvature (C): centre of the sphere of which a lens surface is a part; a lens has two (C_(1), C_(2)).
• Optical centre (O): the central point of the lens; a ray through it passes undeviated.
• Principal axis: the line through both centres of curvature and O.
• Principal focus (F): a lens has two foci, F_(1) and F_(2); the distance OF is the focal length f.
• For a thin lens, the points at 2F_(1) and 2F_(2) are used as the centres of curvature in ray diagrams (radius R = 2f).
• All lens distances are measured from the optical centre.
Do not mix these up
• Lens vs mirror — a mirror has one centre of curvature and one focus; a lens has two of each.
Also asked from this topic: the path of a ray through the optical centre of a thin lens (continues without deviation); the point from which lens distances are measured (the optical centre).
Electricity · Resistors in series and parallel

Q30. If two resistors in series are equal, say R each, what is the total resistance?

  1. (a) 2R
  2. (b) R/2
  3. (c) R
  4. (d) R^(2)
Answer & solution

Answer: (a) 2R

Answer: Option 1 — 2R
In series, resistances simply add: R_(s) = R_(1) + R_(2).
So two equal resistors give R + R = 2R.
Revision note — Series and parallel combinations
• Series: R_(s) = R_(1) + R_(2) + R_(3); same current through each; voltage divides in the ratio of resistances.
• n equal resistors R in series: R_(s) = nR.
• Parallel: 1/R_(p) = 1/R_(1) + 1/R_(2) + 1/R_(3); same voltage across each.
• n equal resistors R in parallel: R_(p) = R/n — two equal ones give R/2.
• Series maximum : parallel minimum for n equal resistors = nR : R/n = n² : 1.
• R_(s) is more than the largest resistor; R_(p) is less than the smallest.
Do not mix these up
• 2R vs R/2 — 2R is two equal resistors in series; R/2 is the same two in parallel.
Also asked from this topic: why resistors are joined in series (to increase total resistance and limit current); current when 3 Ω, 2 Ω and 1 Ω in series are connected to 9 V (1.5 A).
Electricity · Electric power and electrical energy

Q31. Which factor does NOT affect the electric power consumed by an electric device?

  1. (a) Current passing through the device
  2. (b) Voltage applied to the device
  3. (c) Frequency of the device
  4. (d) Resistance of the device
Answer & solution

Answer: (c) Frequency of the device

Answer: Option 3 — Frequency of the device
Electric power is P = V × I = I²R = V²/R.
Only voltage, current and resistance appear, so frequency does not decide the power consumed.
Revision note — Electric power
• Power = rate of using electrical energy; SI unit watt (W) = 1 J/s = 1 V × 1 A.
• Three forms: P = VI, P = I²R (same current, as in series), P = V²/R (same voltage, as in parallel).
• Electrical energy = power × time; commercial unit 1 kWh = 1 unit = 3.6 × 10⁶ J.
• A device rated "100 W, 220 V" uses 100 J every second when run on 220 V.
• In household (parallel) wiring every appliance gets 220 V, so a device with lower resistance draws more power.
Do not mix these up
• Power vs energy — power is in watt; energy is in joule or kWh (the "unit" on the electricity bill).
Also asked from this topic: how to cut the power of a device at a fixed current (decrease its resistance, since P = I²R); the formula for electrical energy (Energy = Power × Time).
Electricity · Resistance, resistivity and their factors

Q32. Which of the following factors directly affects the resistance of a conductor?

  1. (a) Current through the conductor
  2. (b) Length of the conductor
  3. (c) Power of the conductor
  4. (d) Voltage across the conductor
Answer & solution

Answer: (b) Length of the conductor

Answer: Option 2 — Length of the conductor
Resistance is directly proportional to length: R = ρ × L ÷ A.
A longer wire gives the electrons a longer path, so it resists more.
Revision note — Factors that affect resistance
• R ∝ L — doubling the length doubles the resistance.
• R ∝ 1/A — a thicker wire (larger area of cross-section) has less resistance.
• Material — through its resistivity ρ; SI unit of ρ is ohm metre (Ω m).
• Temperature — the resistance of a metal increases as it gets hotter.
• Ohm's law: V = IR; unit of resistance is the ohm (Ω) = 1 volt per ampere.
• Stretching a wire to double its length halves its area, so its resistance becomes 4 times.
Do not mix these up
• Resistance vs V and I — changing the voltage changes the current, but their ratio R = V/I stays the same; V and I do not decide R.
Also asked from this topic: the new resistance when a 4 Ω wire is stretched to double length (16 Ω); the effect of a rise in temperature on a metal's resistance (it increases).
Electricity · Resistance, resistivity and their factors

Q33. Resistance is the property of a material that _______.

  1. (a) converts electrical energy to mechanical energy
  2. (b) allows the flow of current
  3. (c) generates electricity
  4. (d) opposes the flow of current
Answer & solution

Answer: (d) opposes the flow of current

Answer: Option 4 — opposes the flow of current
Resistance is the property of a conductor that opposes the flow of electric current through it.
By Ohm's law, R = V / I; its SI unit is the ohm (Ω).
Revision note — Resistance
• 1 ohm — resistance when 1 V across a conductor drives 1 A through it.
• Resistance depends on length (R ∝ l), area of cross-section (R ∝ 1/A), material and temperature.
• R = ρ l / A; ρ (resistivity) is a property of the material, SI unit Ω m.
• Conductors (copper, silver, aluminium) have low resistivity; alloys such as nichrome have high resistivity.
• Resistance of a metal increases with temperature.
• Series: R = R_(1) + R_(2) + …; parallel: 1/R = 1/R_(1) + 1/R_(2) + …
Also asked from this topic: SI unit of resistance (ohm); resistance of a wire stretched to double its length (4 times); property of good conductors (low resistivity).
Human Eye and the Colourful World · Prism and dispersion of light

Q34. When light exits a prism, what is the result of its interaction with the prism surfaces?

  1. (a) Light passes through without any change.
  2. (b) Light is only reflected.
  3. (c) Light is only absorbed.
  4. (d) Light is refracted.
Answer & solution

Answer: (d) Light is refracted.

Answer: Option 4 — Light is refracted.
Light bends (refracts) as it enters the prism and again as it leaves it.
The two faces are inclined, so the bends add up and the ray is deviated towards the base.
Revision note — Refraction through a glass prism
• At the first face light goes from air to glass and bends towards the normal.
• At the second face it goes from glass to air and bends away from the normal.
• Angle of deviation — angle between the incident ray produced and the emergent ray.
• Angle of the prism — angle between the two refracting faces (commonly 60°).
• Dispersion — white light splits into VIBGYOR; violet deviates most, red least.
• A second, inverted prism recombines the colours into white light (Newton).
Do not mix these up
• Glass slab vs prism — a slab's faces are parallel, so the emergent ray is parallel to the incident ray (only shifted); a prism's are inclined, so the ray is deviated.
Also asked from this topic: where the ray bends inside a prism (towards the base); why the emergent ray is not parallel (inclined refracting faces); splitting of white light (dispersion).
Electricity · Ohm's law

Q35. The current through a resistor is:

  1. (a) proportional to the square root of the resistance
  2. (b) directly proportional to the resistance
  3. (c) inversely proportional to the resistance
  4. (d) proportional to the square of the resistance
Answer & solution

Answer: (c) inversely proportional to the resistance

Answer: Option 3 — inversely proportional to the resistance
By Ohm's law, V = IR, so I = V/R.
For a fixed potential difference, a larger resistance lets less current flow — I ∝ 1/R.
Revision note — Ohm's law and resistance
• Ohm's law (Georg Simon Ohm): at constant temperature, current through a conductor is directly proportional to the potential difference across it — V ∝ I.
• V = IR; the constant R is the resistance, SI unit ohm (Ω) = 1 V/A.
• The V–I graph of an ohmic conductor is a straight line through the origin; its slope gives R.
• Resistance depends on length (R ∝ l), area of cross-section (R ∝ 1/A), material (resistivity ρ) and temperature: R = ρl/A.
• Doubling R at constant V halves I; doubling V at constant R doubles I.
• Current is measured by an ammeter (in series); potential difference by a voltmeter (in parallel).
Do not mix these up
• Resistance vs resistivity — resistance depends on the size and shape of the wire; resistivity (Ω m) depends only on the material and temperature.
Also asked from this topic: what happens to the current when resistance is doubled at constant voltage (it halves); the unit volt per ampere (ohm).
Light - Refraction and Lenses · Convex lens - image formation and uses

Q36. In which case will a lens produce a magnification of exactly 1?

  1. (a) When the object is placed at the focal point
  2. (b) When the object is at infinity
  3. (c) When the object is placed at twice the focal length
  4. (d) When the object is placed between centre of curvature and focal point
Answer & solution

Answer: (c) When the object is placed at twice the focal length

Answer: Option 3 — When the object is placed at twice the focal length
For a convex lens, an object at 2F₁ gives an image at 2F₂.
The image is real, inverted and of the same size — magnification m = −1, i.e. size ratio exactly 1.
Revision note — Image formation by a convex lens
• Object at infinity → image at F₂, highly diminished, real, inverted.
• Object beyond 2F₁ → image between F₂ and 2F₂, diminished, real, inverted.
• Object at 2F₁ → image at 2F₂, same size, real, inverted.
• Object between F₁ and 2F₁ → image beyond 2F₂, enlarged, real, inverted.
• Object at F₁ → image at infinity, highly enlarged.
• Object between F₁ and O → image on the same side, virtual, erect, enlarged — the magnifying glass.
• Magnification m = v/u = h′/h; a negative m means real and inverted, positive means virtual and erect.
Do not mix these up
• m = −1 vs m = +1 — −1 is a real, inverted, same-size image (object at 2F); +1 is what a plane mirror gives (virtual, erect, same size).
Also asked from this topic: where the image forms when the object is at 2F₁ of a convex lens (at 2F₂); where to place the object for a real image twice its size (between F and 2F).
Magnetism and Magnetic Effects of Current · Magnets and magnetic properties

Q37. Why does a compass needle get deflected when brought near a bar magnet?

  1. (a) The compass needle is non-magnetic.
  2. (b) The compass needle is made of iron.
  3. (c) The compass needle is a small bar magnet.
  4. (d) The compass needle has electric charge.
Answer & solution

Answer: (c) The compass needle is a small bar magnet.

Answer: Option 3 — The compass needle is a small bar magnet.
A compass needle is itself a tiny magnet with a north and a south pole.
Near a bar magnet, like poles repel and unlike poles attract, so the needle turns.
Revision note — Magnets and the magnetic compass
• A freely suspended magnet rests in the north–south direction; the north-seeking end is the north pole.
• Like poles repel, unlike poles attract; repulsion is the sure test of a magnet.
• Magnetic field lines go from north to south outside the magnet and south to north inside — they form closed loops.
• Field lines never cross; they are crowded where the field is strong (near the poles).
• A compass is used to trace field lines and to detect a field — Oersted (1820) saw a compass deflect near a current-carrying wire.
• The Earth behaves like a huge magnet whose geographic north has a magnetic south pole — that is why the needle's north end points north.
Do not mix these up
• Iron vs magnet — a plain iron piece is only attracted by a magnet; a compass needle, being a magnet, can be attracted or repelled and so deflects to line up with the field.
Also asked from this topic: what a compass needle deflecting near a straight current-carrying wire shows (a magnetic field is present around the conductor).
Light - Reflection and Mirrors · Spherical mirror terminology

Q38. In which of the following scenarios does the focal length of a concave mirror vary?

  1. (a) Focal length does not vary in any media
  2. (b) When placed in water
  3. (c) When placed in a vacuum
  4. (d) When placed in air
Answer & solution

Answer: (a) Focal length does not vary in any media

Answer: Option 1 — Focal length does not vary in any media
A mirror works by reflection, and the angle of reflection equals the angle of incidence in every medium.
Its focal length depends only on its shape: f = R/2 — so it stays the same in air, water or vacuum.
Revision note — Spherical mirrors
• Pole (P) — centre of the mirror surface; centre of curvature (C) — centre of the sphere it is part of.
• Radius of curvature (R) = PC; focal length (f) = PF; R = 2f for mirrors of small aperture.
• Concave mirror — converging; rays parallel to the axis meet at a real focus in front of the mirror.
• Convex mirror — diverging; the focus is virtual, behind the mirror.
• Mirror formula 1/v + 1/u = 1/f; magnification m = −v/u.
• Uses of concave mirrors: torches and headlights, shaving mirrors, dentist's mirror, solar furnaces; convex mirrors: rear-view mirrors (wider field of view).
Do not mix these up
• Mirror vs lens — a lens works by refraction, so its focal length changes with the surrounding medium (a glass lens in water has a longer focal length); a mirror's focal length does not.
Also asked from this topic: where a parallel beam focuses for a convex mirror of radius of curvature 50 cm (25 cm behind the mirror).

Economics (1)

Industry and Infrastructure · Classification of industries (size, ownership, raw material)

Q39. Which of the following is NOT a private sector company in India?

  1. (a) Tata Iron and Steel Company
  2. (b) Dabur
  3. (c) Bajaj Auto Limited
  4. (d) Bharat Heavy Electricals Limited
Answer & solution

Answer: (d) Bharat Heavy Electricals Limited

Answer: Option 4 — Bharat Heavy Electricals Limited
BHEL is a public sector enterprise owned by the Government of India under the Ministry of Heavy Industries. Tata Steel (formerly TISCO), Dabur and Bajaj Auto are privately owned.
Revision note — Public and private sector industries
• Public sector: owned and run by government agencies — e.g. BHEL, SAIL, ONGC, NTPC, Coal India.
• Private sector: owned by individuals or groups — e.g. Tata Steel, Bajaj Auto, Dabur, Reliance.
• Joint sector: owned jointly by the state and private firms — e.g. Maruti Udyog Ltd.
• Cooperative sector: owned by producers or suppliers — e.g. Amul, sugar mills of Maharashtra.
• BHEL, set up in 1964 with headquarters in New Delhi, is a Maharatna CPSE making power-plant equipment.
• TISCO, set up at Jamshedpur in 1907, is India's oldest private steel company; renamed Tata Steel in 2005.
Do not mix these up
• BHEL vs BEL — BHEL (Heavy Industries) makes power equipment; BEL (Defence) makes defence electronics.
Also asked from this topic: public sector industries (owned and run by government agencies, e.g. SAIL, BHEL); joint sector industries (owned jointly by public and private sectors).

Modern History (1)

Peasant, Tribal and Civil Uprisings · Moplah and Eka movements

Q40. The Moplah Rebellion of 1921 took place in which of the following regions?

  1. (a) Kerala
  2. (b) Bengal
  3. (c) Assam
  4. (d) Punjab
Answer & solution

Answer: (a) Kerala

Answer: Option 1 — Kerala
The Moplah (Mappila) Rebellion of 1921 broke out in the Malabar region, then part of the Madras Presidency and now in Kerala.
The Moplahs were Muslim tenant farmers who rose against British rule and landlords (jenmis).
Revision note — Moplah Rebellion (Malabar Rebellion), 1921
• Began in August 1921 in the Ernad and Valluvanad taluks of Malabar.
• Causes: high rents, insecure tenancy and eviction by jenmi landlords, backed by the British.
• It grew out of the Khilafat and Non-Cooperation agitation of 1920–21.
• Leaders included Variyamkunnath Kunjahammed Haji and Ali Musliyar.
• The Wagon Tragedy (November 1921) — about 60 Moplah prisoners suffocated in a closed railway goods wagon on the way to Podanur.
• The British crushed the revolt by early 1922; it also turned communal in places, which weakened the national movement.
Do not mix these up
• Moplah Rebellion vs Eka Movement — Moplah was in Malabar (Kerala), 1921; Eka ("unity") was a peasant movement in Awadh (UP), 1921–22, led by Madari Pasi.
Also asked from this topic: the region of the 1921 Moplah Rebellion (Malabar); what drove the prolonged Mappila uprisings (harsh land laws and oppression by landlords).

Static GK (2)

Monuments and Heritage · Monuments - builders and locations

Q41. At which of the following places is the tomb of Sher Shah located?

  1. (a) Sasaram
  2. (b) Lahore
  3. (c) Agra
  4. (d) Patna
Answer & solution

Answer: (a) Sasaram

Answer: Option 1 — Sasaram
The tomb of Sher Shah Suri stands at Sasaram in Bihar (Rohtas district), his birthplace region.
It is an octagonal red-sandstone mausoleum set in the middle of an artificial lake.
Revision note — Sher Shah Suri and the Sur Empire
• Founded the Sur Empire (Second Afghan Empire) after defeating Humayun at Chausa (1539) and Kannauj / Bilgram (1540).
• Ruled 1540–1545; died at Kalinjar fort in 1545 during a siege.
• Tomb built in 1545, designed by architect Mir Muhammad Aliwal Khan; a leading example of Indo-Islamic (Afghan) architecture.
• Issued the silver coin rupiya (about 178 grains) and copper dam.
• Built the Sadak-e-Azam (Grand Trunk Road) from Sonargaon (Bengal) to Peshawar, with sarais along it.
• Land revenue by measurement (patta and qabuliyat) — later refined by Todar Mal under Akbar.
Do not mix these up
• Sher Shah's tomb vs Humayun's tomb — Sher Shah's is at Sasaram (Bihar); Humayun's is in Delhi, built by Hamida Banu Begum.
Also asked from this topic: the route of Sher Shah's Grand Trunk Road (Sonargaon to Peshawar); the founder of the Second Afghan (Sur) Empire (Sher Shah Suri).
Books and Authors · Autobiographies and biographies

Q42. Who is the author of 'Segar: Autobiography with Paintings,' published in 2013?

  1. (a) Jhumpa Lahiri
  2. (b) D Raja Segar
  3. (c) Githa Hariharan
  4. (d) Salman Rushdie
Answer & solution

Answer: (b) D Raja Segar

Answer: Option 2 — D Raja Segar
Segar: Autobiography with Paintings is the coffee-table autobiography of the Sri Lankan artist and sculptor D. Raja Segar.
It was released in July 2013 in Colombo, alongside an exhibition of his paintings.
Revision note — D. Raja Segar and his autobiography
• Born 1951 in Colombo, Sri Lanka; he left accountancy to become an artist.
• His style is called "refractive" — cubism in which light seems to bend through geometric shapes.
• Favourite subjects: Buddha, Ganesha and everyday South Asian life.
• He first became known through greeting cards showing Sri Lankan daily life.
• The book traces his rise from poverty to an internationally exhibited artist (Australia, England, India, Sri Lanka).
Also asked from this topic: the author of the autobiography Rasidi Ticket (Amrita Pritam); A Shot at History (Abhinav Bindra); The Race of My Life (Milkha Singh).

Ancient History (1)

Ancient Art, Culture and Science · Stupas and chaityas

Q43. The Great Stupa at Sanchi is an important site in which religion?

  1. (a) Hinduism
  2. (b) Islam
  3. (c) Jainism
  4. (d) Buddhism
Answer & solution

Answer: (d) Buddhism

Answer: Option 4 — Buddhism
The Great Stupa (Stupa No. 1) at Sanchi is one of the oldest Buddhist monuments in India.
A stupa is a hemispherical mound built over relics of the Buddha or of Buddhist monks.
Revision note — The Great Stupa at Sanchi
• Located at Sanchi, Raisen district, Madhya Pradesh, near Vidisha.
• Begun by Ashoka in the 3rd century BCE as a brick stupa; enlarged in stone under the Shungas (2nd century BCE).
• Its four carved gateways (toranas) were added under the Satavahanas in the 1st century BCE.
• The toranas show Jataka stories and scenes from the Buddha's life; the Buddha is shown only by symbols (throne, footprints, Bodhi tree, wheel).
• A UNESCO World Heritage Site since 1989.
• Parts of a stupa: anda (dome), harmika (railed box on top), chhatra (umbrella), vedika (railing), pradakshina path.
Do not mix these up
• Stupa vs chaitya vs vihara — a stupa holds relics; a chaitya is a prayer hall; a vihara is a monastery where monks lived.
Also asked from this topic: what the Sanchi gateway carvings depict (Jataka stories); the state where the Sanchi Stupa stands (Madhya Pradesh); the ruler under whom it was begun (Ashoka).

Geography (1)

India - Location, Physiography and Neighbours · Peninsular plateau and hills

Q44. What is the correct sequence of following mountain ranges of India from north to south?1. Vindhya Range 2. Aravalli Range 3. Ajanta Range 4. Satpura Range

  1. (a) 2, 1, 3, 4
  2. (b) 1, 2, 4, 3
  3. (c) 2, 1, 4, 3
  4. (d) 1, 2, 3, 4
Answer & solution

Answer: (c) 2, 1, 4, 3

Answer: Option 3 — 2, 1, 4, 3
North to south: Aravalli (Rajasthan) → Vindhya (north of the Narmada) → Satpura (between Narmada and Tapi) → Ajanta (Maharashtra, south of the Tapi).
Revision note — Hill ranges of central and western India
• Aravalli — India's oldest fold mountains, running north-east to south-west from Delhi to Gujarat; highest peak Guru Shikhar (1,722 m) on Mount Abu.
• Vindhya — lies north of the Narmada; separates the Ganga basin from the Narmada valley; known for Vindhyan sandstone and limestone.
• Narmada flows east to west in a rift valley between the Vindhya and the Satpura.
• Satpura — between the Narmada and Tapi; highest peak Dhupgarh (1,350 m) at Pachmarhi (Mahadeo Hills); the Tapi rises in the Satpura region.
• Ajanta Range — in Maharashtra, south of the Tapi; the Ajanta caves are cut into it.
• Memory line: A-V-S-A — Aravalli, Vindhya, Satpura, Ajanta from north to south.
Do not mix these up
• Vindhya vs Satpura — Vindhya is north of the Narmada; Satpura is south of it, between Narmada and Tapi.
Also asked from this topic: the oldest mountain range of India (Aravalli); the two river systems the Vindhya separates (Ganga and Narmada).
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