UPSC 2023 Science & Technology Previous Year Questions

Question 1

With reference to green hydrogen, consider the following statements 1. It can be used directly as a fuel for internal combustion. 2. It can be blended with natural gas and used as fuel for heat or power generation. 3. It can be used in the hydrogen fuel cell to run vehicles. How many of the above statements are correct?

Accepted Answer

Correct Option: C. Only one | Only two | All three | None. Green hydrogen can be used in internal-combustion systems, blended with natural gas for heat/power use, and used in fuel cells for vehicles.

Question 2

Consider the following statements regarding mercury pollution: 1. Gold mining activity is a source of mercury pollution in the world. 2. Coal-based thermal power plants cause mercury pollution. 3. There is no known safe level of exposure to mercury. How many of the above statements are correct?

Accepted Answer

Correct Option: B. Only one | Only two | All three | None. Gold mining and coal-based thermal power are recognized sources of mercury pollution. The absolute statement that there is no known safe level of mercury exposure is not accepted for this key, so only two statements are correct.

Question 3

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?

Accepted Answer

Correct Option: D. 1 only | 2 only | Both 1 and 2 | Neither 1 nor 2. Ballistic missiles are rocket-powered and follow ballistic trajectories; cruise missiles are jet-propelled during flight. Agni-V is an intercontinental ballistic missile and BrahMos is a supersonic cruise missile, so both statements are wrong.

Question 4

Which one of the following countries has its own Satellite Navigation System?

Accepted Answer

Correct Option: D. Australia | Canada | Israel | Japan. Japan has its own satellite navigation system, QZSS. The other listed countries do not have comparable independent national systems in this context.

Question 5

Consider the following pairs: 1. Cepheids : Giant clouds of dust and gas in space 2. Nebulae : Stars which brighten and dim periodically 3. Pulsars : Neutron stars that are formed when massive stars run out of fuel and collapse How many of the above pairs are correctly matched?

Accepted Answer

Correct Option: A. Only one | Only two | All three | None. Cepheids are variable stars and nebulae are clouds of gas and dust, so the first two pairs are mismatched. Pulsars are rotating neutron stars formed after massive-star collapse, so only one pair is correct.

Question 6

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?

Accepted Answer

Correct Option: A. Only one | Only two | All three | None. Biofilters mainly provide a substrate for nitrifying bacteria that convert toxic ammonia into nitrate. They do not remove uneaten feed and do not increase phosphorus.

Question 7

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?

Accepted Answer

Correct Option: C. Only one | Only two | All three | None. Accelerometers detect sudden deceleration in crashes, free-fall in devices, and tilt/orientation in smartphones. All three actions use accelerometer functions.

Question 8

Consider the following statements: 1. Carbon fibres are used in the manufacture of components used in automobiles and aircrafts. 2. Carbon fibres once used cannot be recycled. Which of the statements given above is/are correct?

Accepted Answer

Correct Option: A. 1 only | 2 only | Both 1 and 2 | Neither 1 nor 2. Carbon fibre composites are used in automobile and aircraft components. Recycling is difficult but possible, so the absolute statement that they cannot be recycled is incorrect.

Question 9

Consider the following statements in the context of interventions being undertaken under Anaemia Mukt Bharat Strategy: 1. It provides prophylactic calcium supplementation for pre-school children, adolescents and pregnant women. 2. It runs a campaign for delayed cord clamping at the time of child-birth. 3. It provides for periodic deworming to children and adolescents. 4. It addresses non-nutritional causes of anaemia in endemic pockets with special focus on malaria, hemoglobinopathies and fluorosis. How many of the statements given above are correct?

Accepted Answer

Correct Option: C. Only one | Only two | Only three | All four. Anaemia Mukt Bharat includes delayed cord clamping, deworming, and addressing non-nutritional causes such as malaria, hemoglobinopathies and fluorosis. Calcium supplementation is not the stated prophylactic intervention here.

Question 10

Consider the following statements in relation to Janani Suraksha Yojana 1. It is a safe motherhood intervention of the State Health Departments. 2. Its objective is to reduce maternal and neonatal mortality among poor pregnant women. 3. It aims to promote institutional delivery among poor pregnant women. 4. Its objective includes providing public health facilities to sick infants up to one year of age. How many of the statements given above are correct?

Accepted Answer

Correct Option: B. Only one | Only two | Only three | All four. Janani Suraksha Yojana is a centrally sponsored safe motherhood intervention focused on reducing maternal/neonatal mortality and promoting institutional delivery among poor pregnant women. Sick-infant care up to one year belongs to a different intervention, so two are correct.

UPSC 2023 Science & Technology PYQs with Answers