3,238 previous year UPSC Prelims (GS Paper-I) questions, from 1995 to 2025, each with the correct answer and a full explanation. Filter by subject, chapter or year.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 2631–2640 of 3238 questions
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UPSC 2001Indian Economy · External Sector of India
Q2631. Assertion (A): Ceiling on foreign exchange for a host of current account transaction heads was lowered in the year 2000. Reason (R): There was a fall in foreign currency assets also.
Explanation
Assertion (A) is true: According to the annual report of the Reserve Bank of India, 2000, India further liberalized foreign exchange regulations by lowering restrictions on current account transactions under the Foreign Exchange Management Act (FEMA), allowing individuals and businesses greater access to foreign currency for trade, education, medical expenses, and travel. This move was part of India’s economic liberalization process aimed at integrating the country into global markets. Reason (R) is false: During the same period, India’s foreign currency assets were actually increasing due to a steady inflow of foreign direct investment (FDI), robust export growth, and rising remittances from overseas Indians. Hence, the relaxation of current account transaction limits was not due to a fall in foreign currency assets, but rather to boost economic activity and international trade. As per the Reserve Bank of India (RBI) Annual Report 2000, the liberalization of foreign exchange transactions under FEMA was undertaken to enhance India’s trade competitiveness, while foreign exchange reserves continued to rise.
UPSC 2001Science and Technology · Physics: Modern Physics
Q2632. Consider the following statements: In a nuclear reactor, self-sustained chain reaction is possible, because: 1. more neutrons are released in each of the fission reactions. 2. The neutrons immediately take part in the fission process. 3. The fast neutrons are slowed down by graphite. 4. Every neutron released in the fission reaction initiates further fission. Which of these statements are correct?
Explanation
Nuclear fission is the process in which a heavy atomic nucleus, such as uranium-235 or plutonium-239, splits into two smaller nuclei, releasing a large amount of energy.
Statement 1 is correct: Each fission reaction releases multiple neutrons, which are crucial for sustaining the chain reaction.
Statement 2 is correct: The neutrons produced in fission reactions are used to initiate further fission events.
Statement 3 is correct: Graphite (a moderator) slows down fast neutrons, increasing the likelihood that they will cause further fission reactions, thus making reaction sustainable over longer periods.
Statement 4 is incorrect: Not every neutron released will necessarily cause further fission, as some neutrons may escape the reactor or fail to cause fission if not properly moderated.
UPSC 2001Polity · Constitutional Bodies
Q2633. Which one of the following duties is not performed by Comptroller and Auditor general of India?
Explanation
The Comptroller and Auditor General (CAG) of India plays a crucial role in auditing and reporting on the financial transactions of the Indian government. However, some functions fall outside the purview of the CAG’s responsibilities. Statement (a) is correct: The CAG audits and reports on all expenditure from the Consolidated Fund of India, which includes government expenses related to various ministries and departments. Statement (b) is correct: The CAG is responsible for auditing and reporting on all expenditures from the Contingency Funds and Public Accounts. These funds are used for emergency and specific purposes, respectively. Statement (c) is correct: The CAG also audits and reports on trading, manufacturing, and profit and loss accounts of government-owned enterprises and other related entities. Statement (d) is incorrect: The duty of controlling the receipt and disbursement of public money and ensuring public revenue is deposited into the exchequer is managed by other government entities, such as the Ministry of Finance and the Reserve Bank of India.
UPSC 2001Science and Technology · Chemistry: Physical Chemistry
Q2634. In an atom, the order of filling up of the orbitals is governed by:
Explanation
The order of filling up orbitals in an atom is governed by Aufbau’s principle, which states that electrons occupy orbitals in order of increasing energy levels, starting from the lowest energy orbital first. The sequence is determined by the (n + l) rule, where n is the principal quantum number and l is the azimuthal quantum number. If two orbitals have the same (n + l) value, the orbital with the lower n value is filled first.
UPSC 2001Science and Technology · Chemistry: Physical Chemistry
Q2635. A radioactive substance has a half-life of four months. Three-fourth of the substance would decay in:
Explanation
The half-life of a radioactive substance is the time it takes for half of the substance to decay. After each half-life:
At the end of 1 half-life (4 months), 50% of the substance remains. At the end of 2 half-lives (8 months), 25% of the substance remains, meaning 75% (three-fourths) of the substance has decayed. Thus, it takes 8 months for three-fourths of the substance to decay.
UPSC 2001Science and Technology · Chemistry: Physical Chemistry
Q2636. Which one of the following is NOT radioactive?
Explanation
Astatine, Francium, and Tritium are radioactive elements:
Astatine is a halogen with no stable isotopes.
Francium is an alkali metal, highly unstable and radioactive. Tritium is a radioactive isotope of hydrogen. Zirconium is not radioactive. It is a stable, non-radioactive metal widely used in industries like nuclear reactors and construction.
UPSC 2001Polity · Governance
Q2637. Which Article of the Constitution provides that it shall be the endeavour of every state to provide adequate facility for instruction in the mother tongue at the primary stage of education?
Explanation
Option (c) is correct: Article 350-A of the Indian Constitution directs that every state should endeavor to provide adequate facilities for instruction in the mother tongue at the primary stage of education. Options (a), (b) and (d) are incorrect:
Article 349 of the Indian Constitution deals with laws related to language. For 15 years after the Constitution’s commencement, any bill or amendment related to language must receive the President’s prior approval, which is given after considering recommendations from the Commission and the report of the Committee constituted under Article 344. Article 350 of the Indian Constitution ensures that individuals can submit grievances to any authority in the Union or State in a language they’re comfortable with. This provision promotes inclusivity and accessibility, recognizing India’s linguistic diversity and ensuring that language doesn’t become a barrier in seeking justice or redressal Article 351 directs the promotion of the Hindi language and aims to make it a unifying language for India by enriching its vocabulary and usage. It does not deal with the issue of primary education in the mother tongue.
UPSC 2001Geography · Indian Geography
Q2638. Mekong Ganga Cooperation Project is:
Explanation
The Mekong-Ganga Cooperation (MGC) is a regional initiative aimed at enhancing cultural, economic, and tourism ties among member countries. It was launched in 2000 and includes six countries: India, Thailand, Myanmar, Cambodia, Laos, and Vietnam. The project focuses on areas such as tourism, education, culture, and transportation, rather than irrigation, hydroelectric power, or defense.
UPSC 2001Science and Technology · Chemistry: Physical Chemistry
Q2639. Match List I with List II and select the correct answer using the codes given below the lists:
List-I (Characteristic)
List-II (Particle)
A. Zero mass
1. Positron
B. Fractional charge
2. Neutrino
C. Fractional spin
3. Quark
D. Integral spin
4. Photon
Explanation
A is matched with 2: Neutrino is a particle with almost zero mass and no electric charge, making it the correct match for zero mass. B is matched with 3: Quarks are fundamental particles with fractional charges, such as +2/3 or -1/3. C is matched with 1: Positrons, the antimatter counterparts of electrons, possess fractional spin, matching this characteristic. D is matched with 4: Photons are elementary particles of light with an integral spin of 1, classifying them as bosons. Direction: The following item consists of two statements. One labeled as the ‘Assertion (A)’ and the other as "Reason (R). You have to answer this item using the code given below: (2000)
UPSC 2001Geography · Indian Geography
Q2640. Assertion (A): Anticyclonic conditions are formed in the winter season when atmospheric pressure is high and air temperatures are low. Reason (R): Winter rainfall in northern India causes development of anticyclonic conditions with low temperatures.
Explanation
Assertion (A) is true: Anticyclonic conditions are characterized by high atmospheric pressure and sinking air, which leads to clear skies and low temperatures. These conditions are com-mon in winter, especially in northern India after a cyclonic rain from western disturbances. Reason (R) is true: Winter rainfall in northern India, such as the Western Disturbances, is the result of cyclonic (low-pressure) conditions. However, this rain also creates conditions of anticyclonic activity. R correctly explains A: Cyclonic activities beyond the Indian border bring rain to India in winter. This creates a high Pressure area with light winds radiating outwards. This wind creates anticyclonic activity in northern India. Thus, Reason (R) is the correct explanation of Assertion (A).
Additional insight:
Anticyclone Formation: Anticyclones are centers of high pressure. They are surrounded by closed isobars having decreasing pressure outward. The circulation is from central high pressure towards the periphery in such a way that air blows outwards in a clockwise direction in the Northern hemisphere and anticlockwise direction in the southern hemisphere (due to the Coriolis effect). Anticyclones are characterized by stable conditions, warm and dry weather, and gentle winds. Under an anticyclone air is descending, forming an area of higher pressure at the surface. Because of these stable conditions, cloud formation is inhibited, so the weather is usually settled with only small amounts of cloud cover. Summer Anticyclone: In summer the clear settled conditions associated with anticyclones can bring long sunny days and warm temperatures. The weather is normally dry, although occasionally, very hot temperatures can trigger thunderstorms. Winter Anticyclone: In winter the clear, settled conditions and light winds associated with anticyclones can lead to frost and fog.
Answer key for these questions
Q
UPSC year
Correct answer
2631
2001
(c) A is true but R is false
2632
2001
(a) 1, 2 and 3
2633
2001
(d) To control the receipt and issue of public money, and to ensure that the public revenue is lodged in the exchequer
2634
2001
(a) Aufbau’s principle
2635
2001
(c) 8 months
2636
2001
(d) Zirconium
2637
2001
(c) Article 350-A
2638
2001
(b) a joint tourism initiative of some Asian countries
2639
2001
(a) A-2; B-3; C-1; D-4
2640
2001
(a) Both A and R are true and R is the correct explanation of A
Frequently asked questions
How many previous year UPSC questions are there on all subjects?
This page covers 3238 previous year UPSC Prelims GS Paper-I questions on UPSC Prelims GS Paper-I, asked from 1995 to 2025. Each has the correct answer and an explanation.
How should I use previous year UPSC questions for Prelims?
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Which years are covered for all subjects?
Questions on UPSC Prelims GS Paper-I are available for 31 years, from 1995 to 2025. Use the Year filter to practise a single paper.