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Science & Technology

923 questions asked in UPSC Prelims.

2025 · Q64Science & TechnologyComputer & Information Technologydifficult

The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35 ºC. Which of the following statements best reflect(s) the implication of the above-said report? I. Peninsular India will most likely suffer from flooding, tropical cyclones and droughts. II. The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult. Select the correct answer using the code given below.

  1. (a)I only
  2. (b)II only
  3. (c)Both I and II
  4. (d)Neither I nor II
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Official answer(c) Both I and II

2025 · Q81Science & TechnologyRare Earth Elementsmoderate

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?

  1. (a)Both Statement I and Statement II are correct and Statement II explains Statement I
  2. (b)Both Statement I and Statement II are correct but Statement II does not explain Statement I
  3. (c)Statement I is correct but Statement II is not correct
  4. (d)Statement I is not correct but Statement II is correct
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Official answer(a) Both Statement I and Statement II are correct and Statement II explains Statement I

2025 · Q94Science & TechnologySpace Technology & Astronomymoderate

GPS-Aided Geo Augmented Navigation (GAGAN) uses a system of ground stations to provide necessary augmentation. Which of the following statements is/are correct in respect of GAGAN? I. It is designed to provide additional accuracy and integrity. II. It will allow more uniform and high quality air traffic management. III. It will provide benefits only in aviation but not in other modes of transportation. Select the correct answer using the code given below.

  1. (a)I, II and III
  2. (b)II and III only
  3. (c)I only
  4. (d)I and II only
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Official answer(d) I and II only

2024 · Q31Science & TechnologyEnergy & Environmentmoderate

With reference to radioisotope thermoelectric generators (RTGs), consider the following statements : 1. RTGs are miniature fission reactors. 2. RTGs are used for powering the onboard systems of spacecrafts. 3. RTGs can use Plutonium-238, which is a by-product of weapons development. Which of the statements given above are correct ?

  1. (a)1 and 2 only
  2. (b)2 and 3 only
  3. (c)1 and 3 only
  4. (d)1, 2 and 3
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Official answer(b) 2 and 3 only

2024 · Q32Science & TechnologySpace Technology & Astronomymoderate

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 ?

  1. (a)Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
  2. (b)Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  3. (c)Statement-I is correct, but Statement-II is incorrect
  4. (d)Statement-I is incorrect, but Statement-II is correct
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Official answer(d) Statement-I is incorrect, but Statement-II is correct

2024 · Q69Science & TechnologyDefence Technologymoderate

Which of the following is/are correctly matched in terms of equivalent rank in the three services of Indian Defence forces ? Army : Airforce : Navy 1. Brigadier : Air Commodore : Commander 2. Major General : Air Vice Marshal : Vice Admiral 3. Major : Squadron Leader : Lieutenant Commander 4. Lieutenant Colonel : Group Captain : Captain Select the correct answer using the code given below :

  1. (a)1 and 4
  2. (b)1 and 3
  3. (c)2, 3 and 4
  4. (d)3 only
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Official answer(d) 3 only

2023 · Q54Science & TechnologyDefence Technologymoderate

Consider the following actions : 1. Detection of car crash/collision which results in the deployment of airbags almost instantaneously 2. Detection of accidental free fall of a laptop towards the ground which results in the immediate turning off of the hard drive 3. Detection of the tilt of the smart-phone which results in the rotation of display between portrait and landscape mode In how many of the above actions is the function of accelerometer required?

  1. (a)Only one
  2. (b)Only two
  3. (c)All three
  4. (d)None
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Official answer(c) All three

2023 · Q55Science & TechnologyEnergy & Environmentmoderate

With reference to the role of biofilters in Recirculating Aquaculture System, consider the following statements : 1. Biofilters provide waste treatment by removing uneaten fish feed. 2. Biofilters convert ammonia present in fish waste to nitrate. 3. Biofilters increase phosphorus as nutrient for fish in water. How many of the statements given above are correct?

  1. (a)Only one
  2. (b)Only two
  3. (c)All three
  4. (d)None
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Official answer(b) Only two

2023 · Q58Science & TechnologyDefence Technologyeasy

Consider the following statements : 1. Ballistic missiles are jet-propelled at subsonic speeds throughout their flights, while cruise missiles are rocket-powered only in the initial phase of flight. 2. Agni-V is a medium-range supersonic cruise missile, while BrahMos is a solid-fuelled intercontinental ballistic missile. Which of the statements given above is/are correct?

  1. (a)1 only
  2. (b)2 only
  3. (c)Both 1 and 2
  4. (d)Neither 1 nor 2
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Official answer(d) Neither 1 nor 2