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 141–150 of 3238 questions
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UPSC 2024Science and Technology · Nanoscience and Nanotechnology
Q141. In which of the following are hydrogels used? 1. Controlled drug delivery in patients 2. Mobile air-conditioning systems 3. Preparation of industrial lubricants Select the correct answer using the code given below:
Explanation
Hydrogels are three-dimensional polymer networks that can absorb and retain large amounts of water while preserving their structure. With their biocompatibility, flexibility, and customizable properties, they are widely utilized across various applications.
Option 1 is correct: Hydrogels have a porous, water-attracting structure that allows them to expand and contract in response to stimuli. This makes them ideal for controlled drug delivery, ensuring precise and sustained release in liquid environments.
Option 2 is incorrect: Hydrogels are not commonly used in mobile air-conditioning systems. Air-conditioning relies on compressors, refrigerants, and heat exchangers, and though materials with moisture retention might play a minor auxiliary role (like evaporative cooling pads), hydrogels are not a standard component in these systems.
Option 3 is incorrect: Hydrogels do not serve as specific base materials or additives in conventional industrial lubricants. Industrial lubricants typically rely on oils, greases, and synthetic compounds designed for reducing friction and wear. Hydrogels are not chemically or mechanically suited for this purpose. Note: UPSC has given Option(a) as an official answer.
UPSC 2024International Relations and Current Affairs · Current Affairs
Q142. With reference to the Pradhan Mantri Surakshit Matritva Abhiyan, consider the following statements: 1. This scheme guarantees a minimum package of antenatal care services to women in their second and third trimesters of pregnancy and six months post-delivery health care service in any government health facility. 2. Under this scheme, private sector health care providers of certain specialities can volunteer to provide services at nearby government health facilities. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: The Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA) guarantees a minimum package of antenatal care (ANC) services only during pregnancy (second and third trimesters). However, it does not provide health care services for six months post-delivery.
Statement 2 is correct: Under PMSMA, private sector doctors (specialists like gynecologists, radiologists, and physicians) can volunteer to provide free maternal health services at government health facilities on the 9th of every month. This public-private partnership aims to improve access to quality maternal health services.
UPSC 2024Geography · Geomorphology
Q143. Consider the following: 1. Pyroclastic debris 2. Ash and dust 3. Nitrogen compounds 4. Sulphur compounds How many of the above are products of volcanic eruptions?
Explanation
A volcano is an opening or rupture in the Earth’s crust through which molten rock (magma), gases, and ash escape from beneath the surface. When magma reaches the surface, it is called lava. Volcanic eruptions can shape mountains and islands, affecting both the environment and climate. Example:
Mount Etna(Italy), Kilauea (USA) The materials that reach the Earth’s surface in volcanoes include: lava flows pyroclastic debris volcanic bombs ash and dust gases such as nitrogen compounds sulphur compounds minor amounts of chlorine, hydrogen and argon etc.
Exam tip:
You can try, The "NOT" approach for all statements, this tests the improbability of negating a statement--if denying its impact seems highly unlikely, the statement is plausibly true. For example: Can I deny Pyroclastic flow, or gases or ash are not products of Volcanoes? Likely No!, Hence all are likely true.
UPSC 2024International Relations and Current Affairs · Current Affairs
Q144. With reference to the Pradhan Mantri Shram Yogi Maandhan (PM-SYM) Yojana, consider the following statements: 1. The entry age group for enrolment in the scheme is 21 to 40 years. 2. Age specific contribution shall be made by the beneficiary. 3. Each subscriber under the scheme shall receive a minimum pension of Rs. 3,000 per month after attaining the age of 60 years. 4. Family pension is applicable to the spouse and unmarried daughters. Which of the statements given above is/are correct
Explanation
Statement 1 is incorrect: The correct age group for enrollment is 18 to 40 years, not 21 to 40 years.
Statement 2 is correct: The contribution varies based on the age of the beneficiary at the time of joining the scheme. For example, an 18-year-old contributes 55 per month, while a 40-year-old contributes 200 per month.
Statement 3 is correct: After attaining 60 years of age, the subscriber is entitled to a monthly pension of ‘3,000.
Statement 4 is incorrect: Family pension is applicable only to the spouse (50% of the pension amount, i.e., ‘1,500 per month after the subscriber’s death). Unmarried daughters are not included in the family pension provision.
UPSC 2024International Relations and Current Affairs · Current Affairs
Q145. Consider the following airports: 1. Donyi Polo Airport 2. Kushinagar International Airport 3. Vijayawada International Airport In the recent past, which of the above have been constructed as Greenfield projects?
Explanation
Option 1 is correct: Donyi Polo Airport, Itanagar is the first greenfield airport in Arunachal Pradesh. The airport is suitable for all weather day operations.
Option 2 is correct: Since 2019, nearly 6 Greenfield airports namely, Kalaburagi, Orvakal (Kurnool), Sindhudurg, Itanagar, Kushinagar and Mopa have been operationalised, out of which Kushinagar and Mopa airports are International airports.
Option 3 is incorrect: Airport Authority of India has undertaken development/ expansion of airports in Port Blair (Andaman & Nicobar Islands), Vijayawada and Tirupati (Andhra Pradesh), Itanagar and Tezu (Arunachal Pradesh). Thus, Vijayawada airport is not a greenfield project.
UPSC 2024Science and Technology · Space and Space Technology
Q146. Consider the following statements: Statement-I: Giant stars live much longer than dwarf stars. Statement-II: Compared to dwarf stars, giant stars have a greater rate of nuclear reactions. Which one of the following is correct in respect of the above statements?
Explanation
Stars are classified based on their size, mass, and brightness into categories such as giant stars and dwarf stars. Giant stars are massive, highly luminous stars that burn They are often in the later stages of stellar evolution. Dwarf stars, on the other hand, are smaller, less luminous, Red dwarfs, the most common type, can burn for trillions of years, while white dwarfs are the remnants of low to medium-mass stars after they exhaust their nuclear fuel.
Statement I is incorrect: Giant stars have much shorter lifespans than dwarf stars. Giant stars burn fuel quickly because of their high mass and energy, while red dwarf stars use fuel slowly, allowing them to last billions or even trillions of years.
Statement II is correct: Giant stars have much higher core temperatures and pressures, leading to faster nuclear fusion rates compared to dwarf stars. This high rate of fusion results in a shorter lifespan.
Exam tip:
S2 mentions greater rate of nuclear reaction in giant star hence logically it must last less due to early fuel finish, this contradicts with S1. Hence correct answer is either
option C or D. Bigger star=more fuel=more rate of reaction=hence S2 aligns more and S1 likely false.
UPSC 2024Modern History · Indian National Movement III (1930-1947)
Q147. With reference to the Government of India Act, 1935, consider the following statements: 1. It provided for the establishment of an All India Federation based on the union of the British Indian Provinces, and Princely States. 2. Defence and Foreign Affairs were kept under the control of the federal legislature. Which of the statements given above is/are correct?
Explanation
The Government of India Act was passed by the British parliament in 1935 and came into effect in 1937. It was based on a report by a Joint Select Committee, led by Lord Linlithgow, set up the two houses of the British parliament. Some of the key features of the Act were:
The creation of a ‘Federation of India’ that consisted of two levels: a central executive and parliament, and below it, provinces and princely states. Hence, Statement 1 is correct. It discarded the ‘dyarchy’ system at the provincial level and allowed for the emergence of popularly elected provincial legislatures. Dyarchy was introduced at the central level, key subjects like defence and foreign affairs were under the direct control of the Governor General. Hence, Statement 2 is incorrect. A federal court was established. The franchise was expanded to 14% of the population from 3%. Separate electorates were provided for Muslims, Sikhs and others, but not to Depressed Classes. The governor enjoyed critical emergency powers.
Exam tip:
For S2, Would the British Empire in 1935 be willing to hand over Defence and Foreign Affairs -- its most critical imperial powers -- to an Indian legislature? Unlikely Hence plausibly false.
UPSC 2024Environment and Ecology · Environmental Laws, Conventions and Policies
Q148. Consider the following statements: Statement-I: The Indian Flying Fox is placed under the "vermin" category in the Wild Life (Protection) Act, 1972. Statement-II: The Indian Flying Fox feeds on the blood of other animals. Which one of the following is correct in respect of the above statements?
Explanation
Note: Vermin category listed in Schedule V of the Wild-life Protection Act, 1972 has been removed after the Wildlife Protection Amendment Act 2022, as now there are only 4 schedules in WPA. Hence the answer is subject to considerations made by the Commission.
Statement 1 is correct: The Indian Flying Fox is placed under the "vermin" category in the Wild Life (Protection) Act, 1972 due to its destructive tendencies towards fruit farms.
Statement 2 is incorrect: Bats are the only flying mammals in the world, and the Indian Flying Fox is one of the largest. The species, Pteropus giganteus, also called the Great Indian Fruit Bat, eats fruits, feeding on the juice, and helps in seed dispersion and pollination, making them an integral part of the ecosystem.
Additional insight:
The Wild Life (Protection) Act, 1972, is an important environmental legislation in India aimed at protecting wildlife, conserving biodiversity, and regulating the trade of wild animals and their products. Some key changes done through Wild life (Protection) Amendment Act, 2022 are:
Aligned the Act with the Convention on International Trade in Endangered Species (CITES). Reduced the number of schedules for animals from six to four. The Wild Life (Protection) Amendment Act, 2022 removed the schedule listing vermin species from the original Wild Life (Protection) Act, 1972. Previously, Schedule V of the Act designated certain species as vermin, allowing them to be hunted freely. The 2022 Amendment streamlined the schedules, eliminating the separate vermin category.
UPSC 2024Environment and Ecology · Environmental Laws, Conventions and Policies
Q149. According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?
Explanation
Emissions that lead to high concentrations of SO₂ generally also lead to the formation of other SOx. The largest sources of SO₂ emissions are from fossil fuel combustion at power plants and other industrial facilities. EPA’s national ambient air quality standards for SO₂ are designed to protect against exposure to the entire group of sulfur oxides (SOx). SO₂ is the component of greatest concern and is used as the indicator for the larger group of gaseous sulfur oxides (SOx). Other gaseous SOx (such as SO₃) are found in the atmosphere at concentrations much lower than SO₂.
UPSC 2024Indian Economy · Money Market
Q150. With reference to the Indian economy, "Collateral Borrowing and Lending Obligations" are the instruments of:
Explanation
Collateralized Borrowing and Lending Obligations (CBLO) are short-term money market instruments used for borrowing and lending funds. They are primarily used by financial institutions such as banks, mutual funds, and insurance companies to manage liquidity. CBLO transactions are collateralized, meaning they require securities (such as government bonds) as collateral, reducing credit risk. The instrument was introduced by the Clearing Corporation of India Ltd. (CCIL) to facilitate secure and efficient borrowing and lending of funds in the money market. CBLOs facilitate borrowing and lending transactions that are fully collateralized, typically using government securities as collateral. CBLOs are primarily used by financial institutions to man-age liquidity and funding needs over short durations, ranging from overnight to one year.
Additional insight:
Bond Market: The bond market is a financial marketplace where governments, corporations, and other entities issue and trade debt securities (bonds) to raise capital. Investors lend money to issuers in exchange for periodic interest payments and the return of the principal at maturity. Bonds are categorized into government bonds, corporate bonds, municipal bonds, and asset-backed securities. Forex Market: The foreign exchange (forex) market is a global decentralized platform for trading currencies. It facilitates currency exchange for trade, investment, speculation, and hedging against currency risks. The market includes spot transactions, forward contracts, futures, options, and swaps. Stock Market: The stock market is a marketplace where shares of publicly listed companies are bought and sold. It consists of the primary market (where companies issue shares through IPOs) and the secondary market (where existing shares are traded). Investors profit through dividends or capital gains as share prices fluctuate. Stocks, exchange-traded funds (ETFs), mutual funds etc are traded in the Stock market.
Answer key for these questions
Q
UPSC year
Correct answer
141
2024
(d) 1, 2 and 3
142
2024
(b) 2 only
143
2024
(d) All four
144
2024
(b) 2 and 3 only
145
2024
(a) 1 and 2 only
146
2024
(d) Statement-I is incorrect, but Statement-II is correct
147
2024
(a) 1 only
148
2024
(c) Statement -I is correct, but Statement-II is incorrect
149
2024
(d) Power plants using fossil fuels
150
2024
(c) Money market
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.
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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.