UPSC 2013 Science & Technology Previous Year Questions

Question 1

The efforts to detect the existence of Higgs boson particle have become frequent news in the recent past. What is/are the importance/importances of discovering this particle? 1. It will enable us to understand as to why elementary particles have mass. 2. It will enable us in the near future to develop the technology of transferring matter from one point to another without traversing the physical space between them. 3. It will enable us to create better fuels for nuclear fission. Select the correct answer using the codes given below.

Accepted Answer

Correct Option: A. 1 only | 2 and 3 only | 1 and 3 only | 1, 2 and 3. The Higgs boson is important because it helps explain how elementary particles acquire mass through the Higgs field. It does not imply teleportation technology or better nuclear fission fuels.

Question 2

The known forces of nature can be divided into four classes, viz., gravity, electromagnetism, weak nuclear force and strong nuclear force. With reference to them, which one of the following statements is not correct?

Accepted Answer

Correct Option: A. Gravity is the strongest of the four | Electromagnetism acts only on particles with an electric charge | Weak nuclear force causes radioactivity | Strong nuclear force holds protons and neutrons inside the nucleus of an atom. Gravity is actually the weakest of the four fundamental forces, not the strongest. The other statements correctly describe electromagnetism, weak nuclear force and strong nuclear force.

Question 3

Which of the following statements is/are correct? 1. Viruses lack enzymes necessary for the generation of energy 2. Viruses can be cultured in any synthetic medium. 3. Viruses are transmitted from one organism to another by biological vectors only. Select the correct answer using the codes given below.

Accepted Answer

Correct Option: A. 1 only | 2 and 3 only | 1 and 3 only | 1, 2 and 3. Viruses lack their own metabolic machinery and enzymes for energy generation. They require living host cells, cannot be cultured in ordinary synthetic media, and can spread by multiple routes, not only biological vectors.

Question 4

Many transplanted seedlings do not grow because

Accepted Answer

Correct Option: C. the new soil does not contain favourable minerals | most of the root hairs grip the new soil too hard | most of the root hairs are lost during transplantation | leaves get damaged during transplantation. Root hairs absorb water and minerals but are delicate and often lost during transplantation. Loss of root hairs prevents seedlings from establishing in new soil.

Question 5

Rainbow is produced when sunlight falls on drops of rain. Which of the following physical phenomena are responsible for this? 1. Dispersion 2. Refraction 3. Internal reflection Select the correct answer using the codes given below.

Accepted Answer

Correct Option: D. 1 and 2 only | 2 and 3 only | 1 and 3 only | 1, 2 and 3. A rainbow forms when sunlight is refracted entering raindrops, dispersed into colours and internally reflected before emerging. All three phenomena are involved.

Question 6

Consider the following phenomena: 1. Size of the sun at dusk 2. Colour of the sun at dawn 3. Moon being visible at dawn 4. Twinkle of stars in the sky 5. Polestar being visible in the sky Which of the above are optical illusions?

Accepted Answer

Correct Option: C. 1, 2 and 3 | 3, 4 and 5 | 1, 2 and 4 | 2, 3 and 5. The apparent larger size of the sun at dusk, red/orange colour at dawn due scattering perception, and twinkling stars due atmospheric refraction are optical phenomena/illusions. The moon or Polestar being visible is not an illusion.

Question 7

Ball bearings are used in bicycles, cars, etc., because

Accepted Answer

Correct Option: C. the actual area of contact between the wheel and axle is increased | the effective area of contact between the wheel and axle is increased | the effective area of contact between the wheel and axle is reduced | None of the above statements is correct. Ball bearings convert sliding friction into rolling friction and reduce the effective contact area between moving parts. This reduces friction in wheels and axles.

Question 8

Fruits stored in a cold chamber exhibit longer storage life because

Accepted Answer

Correct Option: C. exposure to sunlight is prevented | concentration of carbon dioxide in the environment is increased | rate of respiration is decreased | there is an increase in humidity. Cold storage lowers the respiration and metabolic rate of fruits, delaying ripening and decay. This extends storage life.

Question 9

During a thunderstorm, the thunder in the skies is produced by the 1. meeting of cumulonimbus clouds in the sky 2. lightning that separates the nimbus clouds 3. violent upward movement of air and water particles Select the correct answer using the codes given below.

Accepted Answer

Correct Option: D. 1 only | 2 and 3 | 1 and 3 | None of the above produces the thunder. Thunder is produced by the sudden heating and rapid expansion of air around lightning, which creates a shock wave. None of the listed statements accurately states this cause.

Question 10

Consider the following minerals: 1. Calcium 2. Iron 3. Sodium Which of the minerals given above is/are required by human body for the contraction of muscles?

Accepted Answer

Correct Option: D. 1 only | 2 and 3 only | 1 and 3 only | 1, 2 and 3. Muscle contraction requires calcium for actin-myosin interaction, sodium for nerve impulse transmission and membrane potential, and iron indirectly through oxygen transport and muscle metabolism. The official key includes all three.

UPSC 2013 Science & Technology PYQs with Answers