UPSC 2025 Science and Technology Questions with Answers
13 previous year UPSC Prelims questions on Science and Technology in the UPSC 2025 Prelims. Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 11–13 of 13 questions
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UPSC 2025Science and Technology · Miscellaneous
Q11. Consider the following statements: Statement I: Some rare earth elements are used in the manufacture of flat television, screens and computer monitors. Statement II: Some rare earth elements have phosphorescent properties. Which one of the following is correct in respect of the above statements?
Explanation
Rare earth elements (REEs) are a group of 17 chemically similar metallic elements that are known for their high luster, high density, and unique magnetic, phosphorescent, and catalytic properties.
Statement 1 is correct: Rare earth elements such as europium, terbium, and yttrium are crucial for producing the bright, vivid colors in modern flat screens and monitors.
Statement 2 is correct: Many rare earth elements, like europium and terbium, have phosphorescent or luminescent properties, meaning they can absorb energy and emit light, which is used in various applications including displays.
Additional insight:
Uses of Rare-earth Metals Rare-earth metals play a vital role across multiple sectors, including electronics, renewable energy, and automotive industries. They are indispensable for manufacturing high-performance magnets used in electric vehicle motors and wind turbines, and are also key components in efficient lighting like fluorescent lamps. In electronics, rare-earth metals are essential for producing smartphones, computers, and other devices, enabling smaller sizes, better performance, and greater energy efficiency. Their unique magnetic and catalytic properties also make them crucial for renewable energy technologies, such as wind turbines, solar panels, and electric vehicle batteries, enhancing the effectiveness and sustainability of these systems.
Exam tip:
Anytime a statement uses "some" (not "all"), it makes it logically hard to disprove. Hence likely true. Combine that with cause-effect linkage (screens need light rare earths emit light), and you arrive at the right answer option A.
UPSC 2025Science and Technology · Space and Space Technology
Q12. Consider the following space missions: I. Axiom-4 II. SpaDeX III. Gaganyaan How many of the space missions given above encourage and support micro-gravity research?
Explanation
Microgravity research refers to scientific studies conducted in environments where the force of gravity is extremely low, causing objects and people to appear weightless. In such conditions, often found in space or simulated on Earth, researchers can observe how physical, chemical, and biological systems behave differently than they do under normal gravity. Options 1, 2, and 3 are correct:
Axiom-4 is a private mission to the ISS that will conduct around 60 scientific studies, including several led by ISRO, with a strong focus on microgravity research across various disciplines such as biology, medicine, and materials science. ISRO and ESA are collaborating on microgravity research experiments specifically for Axiom-4. SpaDeX is an ISRO technology demonstrator for in-space docking. The mission uses the PSLV’s fourth stage (POEM-4) to carry 24 payloads from academia and startups, which will utilize the microgravity environment in orbit for scientific experiments. The mission explicitly provides opportunities for in-orbit microgravity experiments for extended durations. Gaganyaan is India’s first human spaceflight mission, led by ISRO. Scheduled to send Indian astronauts into low Earth orbit, it aims to demonstrate indigenous capability in crewed space missions. Gaganyaan will also facilitate scientific research in microgravity, marking a significant milestone in India’s space exploration journey.
Exam tip:
If a mission goes to space (especially to ISS or LEO), microgravity is either used, tested, or researched -- even if not the main goal. Hence, All three missions likely qualify to encourage and support micro-gravity research under this logic.
UPSC 2025Science and Technology · Defence Technology
Q13. With reference to India’s defence, consider the following pairs:
Aircraft type
Description
I. Dornier-228
Maritime patrol aircraft
II. IL-76
Supersonic combat aircraft
III. C-17 Globemaster III
Military transport aircraft
How many of the pairs given above are correctly matched?
Explanation
Pair 1 is correctly matched: Dornier -228 is known for their versatility, they are equipped for a range of missions, including maritime patrol, surveillance, pollution control, search and rescue, and medical evacuation.
Pair 2 is not correctly matched: The Ilyushin Il-76 is a strategic/heavy military transport aircraft, not a supersonic combat aircraft. HAL Tejas, MiG-21, Sukhoi Su-30MKI and Dassault Rafale are examples of supersonic combat aircraft.
Pair 3 is correctly matched: The C-17 Globemaster III is a large military transport aircraft used for airlift and cargo missions. The Indian Air Force (IAF) has received its third Boeing C-17 Globemaster III, a large, versatile military transport aircraft capable of carrying heavy, oversize loads long distances and landing on rough and unprepared surfaces.
Additional insight:
Maritime Patrol Aircraft: A maritime patrol aircraft is a fixed-wing aircraft designed for extended operations over water, primarily performing maritime surveillance, anti-submarine warfare, anti-ship warfare, and search and rescue missions. They are equipped with sensors like radar, sonobuoys, and magnetic anomaly detectors for effective maritime reconnaissance. Supersonic Combat Aircraft: Supersonic combat aircraft are military jets capable of flying faster than the speed of sound (Mach 1). These aircraft, such as fighter jets, are designed for air-to-air or air-to-ground combat and utilize advanced aerodynamics to operate efficiently at supersonic speeds. Military Transport Aircraft: Military transport aircraft, also known as airlifters, are used to move troops, equipment, and supplies to support military operations. They play a vital role in maintaining supply lines, conducting strategic and tactical missions, and providing humanitarian aid during emergencies.
Answer key for these questions
Q
UPSC year
Correct answer
11
2025
(a) Both Statement I and Statement II are correct and Statement II explains Statement I
12
2025
(c) All the three
13
2025
(b) Only two
Frequently asked questions
How many previous year UPSC questions are there on Science and Technology?
This page covers 13 previous year UPSC Prelims GS Paper-I questions on Science and Technology in the UPSC 2025 Prelims, asked from 1996 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 Science and Technology?
Questions on Science and Technology in the UPSC 2025 Prelims are available for 30 years, from 1996 to 2025. Use the Year filter to practise a single paper.
