UPSC Prelims Previous Year Questions 2024: Science & Technology | UPSC Topic Wise Previous Year Questions PDF Download

Q1: Which one of the following words/phrases is most appropriately used to denote “an interoperable network of 3D virtual worlds that can be accessed simultaneously by millions of users, who can exert property rights over virtual items”?
(a) Big data analytics
(b) Cryptography
(c) Metaverse
(d) Virtual matrix

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Ans: (c)
Metaverse is most appropriately used to describe an interoperable network of 3D virtual worlds, where users can interact, access simultaneously, and exert property rights over virtual items.

Q2: 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 developments.

Which of the statements given above are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

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Ans: (b)
Radioisotope Thermoelectric Generators (RTGs) use Plutonium-238 for power, and they are utilized to power spacecraft systems, but they are not miniature fission reactors. Instead, they rely on the heat released by radioactive decay, not fission reactions.

• Statement 1 is incorrect because RTGs are not fission reactors.
• Statements 2 and 3 are correct.

Q3: 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?
(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
(c)  Statement-I is correct, but Statement-II is incorrect
(d)  Statement-I is incorrect, but Statement-II is correct

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Ans: (d)
Giant stars have a greater rate of nuclear reactions compared to dwarf stars, which results in a shorter lifespan. Therefore, Statement-I is incorrect, but Statement-II is correct.

Q4: Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow?
(a) Nitric oxide
(b) Nitrous oxide
(c) Nitrogen dioxide
(d) Nitrogen pentoxide

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Ans: (a)
Nitric oxide (NO) is synthesized in the human body and plays a role in dilating blood vessels, thus increasing blood flow.

Q5: Consider the following activities:

1. Identification of narcotics on passengers at airports or in aircraft
2. Monitoring of precipitation
3. Tracking the migration of animals

In how many of the above activities can the radars be used?
(a) Only one
(b) Only two
(c) All three
(d) None

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Ans: (c)
Radars can be used for multiple purposes:

• Identifying narcotics on passengers at airports (through detection technologies).
• Monitoring precipitation (using weather radar).
• Tracking migration of animals (radar can track large animal movements).

Therefore, radars can be used for all three activities.

Q6: Consider the following aircraft:

1. Rafael
2. MiG-29
3. Tejas MK-1

How many of the above are considered fifth generation fighter aircraft?
(a) Only one
(b) Only two
(c) All three
(d) None

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Ans: (d)
Fifth-generation fighter aircraft are characterized by advanced stealth, speed, and sensors. None of the mentioned aircraft—Rafale, MiG-29, or Tejas MK-1—are classified as fifth-generation fighter aircraft. They belong to earlier generations.

Q7: 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:
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3

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Ans: (d)
Hydrogels are used in a variety of applications:

• Controlled drug delivery in medical treatments.
• Mobile air-conditioning systems for their ability to absorb moisture.
• Industrial lubricants preparation due to their water retention properties.

Q8: Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen?
(a) Hydrogen peroxide
(b) Hydronium
(c) Oxygen
(d) Water vapour

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Ans: (d)
The exhaust pipe emission from Fuel Cell Electric Vehicles (FCEVs) powered by hydrogen is water vapor, as hydrogen reacts with oxygen to produce water.

Q9: Recently, the term “pumped-storage hydropower” is actually and appropriately discussed in the context of which one of the following?
(a) Irrigation of terraced crop fields
(b) Lift irrigation of cereal crops
(c) Long duration energy storage
(d) Rainwater harvesting system

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Ans: (c)
Pumped-storage hydropower is a technology used for long-duration energy storage, where water is pumped to a higher elevation during periods of low energy demand and released to generate electricity during peak demand.

Q10:  “Membrane Bioreactors” are often discussed in the context of :
(a) Assisted reproductive technologies
(b) Drug delivery nanotechnologies
(c) Vaccine production technologies
(d) Wastewater treatment technologies

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Ans: (d)
Membrane Bioreactors are commonly discussed in the context of wastewater treatment technologies because they combine membrane filtration and biological processes to treat water efficiently.