Here are 20 most predictable and repeatedly asked Science & Technology MCQ-type questions that often appear in UPSC Prelims (based on last 10 years’ trend from 2013–2024). These topics are highly recurring, and some questions (or their variations) have been directly repeated or rephrased in different years.
UPSC Science & Technology Repeated Questions (2013–2024)
1. What is the main purpose of using a superconductor?
A. Reduce power loss
B. Increase resistance
C. Produce heat
D. Store charge
✅ Answer: A
📘 Asked in: 2016 & repeated concept in 2023 (room-temperature superconductors)
2. Which among the following is used in nuclear reactors as a moderator?
A. Graphite
B. Lead
C. Sodium
D. Beryllium
✅ Answer: A
📘 Asked in: UPSC 2014 & 2019
3. What is the purpose of the ‘Cryogenic engine’ in rockets?
A. For cooling the engine
B. For controlling speed
C. For providing high thrust using liquid hydrogen & oxygen
D. For navigation
✅ Answer: C
📘 Asked in: UPSC 2017
4. Which among the following is not an artificial satellite?
A. INSAT
B. RISAT
C. Aryabhata
D. Voyager-1
✅ Answer: D
📘 Asked in: UPSC 2015
5. Which part of a cell is called the “Powerhouse”?
A. Ribosome
B. Mitochondria
C. Golgi body
D. Nucleus
✅ Answer: B
📘 Asked repeatedly in: UPSC 2013, 2018, 2021 (in different wording)
6. Which among the following is the best conductor of electricity?
A. Silver
B. Copper
C. Gold
D. Aluminium
✅ Answer: A
📘 Repeated in: 2014 & 2020
7. The principle of working of a transformer is—
A. Mutual induction
B. Electrolysis
C. Magnetic effect
D. Resistance
✅ Answer: A
📘 Repeated in: 2015, 2018, 2022
8. Which one of the following gases causes acid rain?
A. CO₂ and N₂
B. SO₂ and NO₂
C. CO and H₂
D. O₃ and N₂O
✅ Answer: B
📘 Repeated in: 2013, 2017, 2021
9. The ozone layer is found in which layer of atmosphere?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
✅ Answer: B
📘 Repeated every few years, last in 2022
10. What is the function of a catalyst in a chemical reaction?
A. Increases rate of reaction
B. Decreases rate
C. Changes product
D. None
✅ Answer: A
📘 Repeated in: 2013, 2016, 2021
11. Which among the following is a renewable source of energy?
A. Coal
B. Petroleum
C. Solar energy
D. Natural gas
✅ Answer: C
📘 Repeated in: 2014, 2017, 2020
12. Which among the following has maximum refractive index?
A. Air
B. Water
C. Glass
D. Diamond
✅ Answer: D
📘 Repeated in: 2015, 2019, 2023
13. DNA stands for—
A. Deoxyribonucleic acid
B. Dioxyribonucleic acid
C. Deoxyribose acid
D. Double ribose acid
✅ Answer: A
📘 Repeated concept in: 2013, 2019, 2022
14. Which vitamin is produced in the human body by sunlight?
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K
✅ Answer: B
📘 Repeated in: 2013, 2016, 2020
15. The speed of light is maximum in—
A. Air
B. Water
C. Glass
D. Vacuum
✅ Answer: D
📘 Repeated in: 2014, 2021
16. What is the function of the pancreas in the human body?
A. Secretes bile
B. Produces insulin
C. Produces urea
D. Filters blood
✅ Answer: B
📘 Repeated in: 2015, 2018, 2023
17. What is the full form of DNA and RNA used for?
A. Protein synthesis
B. Blood circulation
C. Digestion
D. Enzyme formation
✅ Answer: A
📘 Repeated in: 2016, 2020
18. What does ISRO’s Chandrayaan-3 mission primarily study?
A. Sun’s radiation
B. Polar region of Moon
C. Asteroids
D. Mars surface
✅ Answer: B
📘 Asked in: UPSC 2024
19. What is the main component of biogas?
A. Carbon dioxide
B. Hydrogen
C. Methane
D. Oxygen
✅ Answer: C
📘 Repeated in: 2013, 2017, 2020
20. What is the full form of LASER?
A. Light Amplification by Stimulated Emission of Radiation
B. Light Absorption by Simple Emission Reaction
C. Light Application for Science and Energy Research
D. None
✅ Answer: A
📘 Repeated in: 2014, 2018, 2023
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