UPSC 2012 Science & Technology Previous Year Questions

Question 1

Consider the following statements: If there were no phenomenon of capillarity: 1. it would be difficult to use a kerosene lamp. 2. one would not be able to use a straw to consume a soft drink. 3. the blotting paper would fail to function. 4. the big trees that we see around would not have grown on the Earth. Which of the statements given above are correct?

Accepted Answer

Correct Option: B. 1, 2 and 3 only | 1, 3 and 4 only | 2 and 4 only | 1, 2, 3 and 4. Capillarity allows kerosene to rise in a lamp wick, enables blotting paper to absorb ink and helps water move through fine spaces in soil/plant tissues. Drinking through a straw depends mainly on pressure difference, not capillarity.

Question 2

Recently, there has been a concern over the short supply of a group of elements called rare earth metals. Why? 1. China, which is the largest producer of these elements, has imposed some restrictions on their export. 2. Other than China, Australia, Canada and Chile, these elements are not found in any country. 3. Rare earth metals are essential for the manufacture of various kinds of electronic items and there is a growing demand for these elements. Which of the statements given above is/are correct?

Accepted Answer

Correct Option: C. 1 only | 2 and 3 only. | 1 and 3 only | 1, 2 and 3. China has dominated rare earth production and export restrictions caused supply concerns. Rare earths are used in electronics and clean technologies. They occur in several countries beyond the few listed, so statement 2 is false.

Question 3

Other than resistance to pests, what are the prospects for which genetically engineered plants have been created? 1. To enable them to withstand drought 2. To increase the nutritive value of the produce 3. To enable them to grow and do photosynthesis in spaceships and space stations 4. To increase their shelf life Select the correct answer using the codes given below:

Accepted Answer

Correct Option: C. 1 and 2 only | 3 and 4 only | 1,2 and 4 only | 1, 2, 3 and 4. Genetic engineering has been used to develop drought tolerance, enhanced nutrition and longer shelf life. Space-station photosynthesis is not a standard prospect represented in this question.

Question 4

The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs

Accepted Answer

Correct Option: D. the water vapour of the air and retains its heat | the ultraviolet part of the solar radiation | all the solar radiations | the infrared part of the solar radiation. Carbon dioxide is a greenhouse gas because it absorbs outgoing long-wave infrared radiation emitted by Earth. This traps heat and raises atmospheric temperature.

Question 5

To meet its rapidly growing energy demand, some opine that India should pursue research and development on thorium as the future fuel of nuclear energy. In this context, what advantage does thorium hold over uranium?

1. Thorium is far more abundant in nature than uranium.
2. On the basis of per unit mass of mined mineral, thorium can generate more energy compared to natural uranium.
3. Thorium produces less harmful waste compared to uranium.

Which of the statements given above is/are correct?

Accepted Answer

Correct Option: D. 1 only | 2 and 3 only | 1 and 3 only | 1, 2 and 3. Thorium is abundant in India, can yield more usable energy per mined mass in a breeder fuel cycle, and produces comparatively less long-lived transuranic waste. These advantages explain interest in thorium.

Question 6

Electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth?

Accepted Answer

Correct Option: A. The Earth's magnetic field diverts them towards its poles | Ozone layer around the Earth reflects them back to outer space | Moisture in the upper layers of atmosphere prevents them from reaching the surface of the Earth | None of the statements (a), (b) and (c) given above is correct. Earth's magnetic field deflects charged solar and cosmic particles toward polar regions, preventing most from reaching the surface directly. Ozone mainly absorbs UV radiation, not charged partic

Question 7

Which of the following is/are cited by the scientists as evidence/evidences for the continued expansion of universe? 1. Detection of microwaves in space. 2. Observation of redshift phenomenon in space. 3. Movement of asteroids in space. 4. Occurrence of supernova explosions in space. Select the correct answer using the codes given below:

Accepted Answer

Correct Option: A. 1 and 2 | 2 only | 1, 3 and 4 | None of the above can be cited as evidence. Cosmic microwave background radiation and redshift of distant galaxies are major evidence for an expanding universe. Asteroid movement and supernova occurrence by themselves are not cited as general evidence of continued expansion in this context.

Question 8

A team of scientists at Brookhaven National Laboratory including those from India created the heaviest anti-matter (anti-helium nucleus). What is/are the implication/implications of the creation of anti-matter? 1. It will make mineral prospecting and oil exploration easier and cheaper. 2. It will help probe the possibility of the existence of stars and galaxies made of anti-matter. 3. It will help understand the evolution of the universe. Select the correct answer using the codes given below:

Accepted Answer

Correct Option: B. 1 only | 2 and 3 only | 3 only | 1, 2 and 3. Creating anti-helium helps scientists study antimatter and test whether antimatter stars or galaxies could exist, and it informs understanding of matter-antimatter asymmetry in the early universe. It is not useful for mineral or oil exploration.

Question 9

With reference to 'stem cells', frequently in the news, which of the following statements is/are correct? 1. Stem cells can be derived from mammals only. 2. Stem cells can be used for screening new drugs. 3. Stem cells can be used for medical therapies. Select the correct answer using the codes given below:

Accepted Answer

Correct Option: B. 1 and 2 only | 2 and 3 only | 3 only | 1, 2 and 3. Stem cells are found in many organisms, not mammals only. They are widely used for drug screening and have therapeutic applications in regenerative medicine and treatment research.

Question 10

Lead, ingested or inhaled, is a health hazard. After the addition of lead to petrol has been banned, what still are the sources of lead poisoning? 1. Smelting units 2. Pens and pencils 3. Paints 4. Hair oils and cosmetics Select the correct answer using the codes given below:

Accepted Answer

Correct Option: B. 1, 2 and 3 only | 1 and 3 only | 2 and 4 only | 1, 2, 3 and 4. Lead exposure can come from smelting units and lead-based paints. Ordinary pens and pencils are not typical lead-poisoning sources, and the official key does not include hair oils/cosmetics here.

UPSC 2012 Science & Technology PYQs with Answers