# Test: Physics (2018 - 2011)

## 15 Questions MCQ Test Science & Technology for UPSC CSE | Test: Physics (2018 - 2011)

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Attempt Test: Physics (2018 - 2011) | 15 questions in 20 minutes | Mock test for UPSC preparation | Free important questions MCQ to study Science & Technology for UPSC CSE for UPSC Exam | Download free PDF with solutions
QUESTION: 1

### With reference to solar power production in India, consider the following statements: 1. India is the third largest in the world in the manufacture of silicon wafers used in photovoltaic units. 2. The solar power tariffs are determined by the Solar Energy Corporation of India Which of the statements given above is/are correct? [2018]

Solution:

(i) There is no significant production of silicon wafers in India (as of 2011). So unlikely that it became 3rd largest by 2017-18. So, #1 is wrong.
(ii) Tariffs are determined under the Electricity Act. Any entity with "Corporation" word is irrelevant. so, #2 is wrong.

QUESTION: 2

### Consider the following phenomena: 1. Light is affected by gravity. 2. The Universe is constantly expanding. 3. Matter warps its surrounding space-time. Which of the above is/are the prediction/predictions of Albert Einstein's General Theory of Relativity, often discussed in media? [2018]

Solution:

(i) 2010: International Team of Astronomers confirmed Albert Einstein's theory of general relativity and that the expansion of the universe is accelerating after looking at data from the Hubble Space Telescope.
There is an unknown source of energy in the universe which is causing the cosmic expansion to speed up.
(ii) 2016: Japanese researchers' study finds that the expansion of the universe could be explained by a cosmological constant, as proposed by Einstein in his theory of general relativity. So second statement is right. This eliminates B and (C)
(iii) 2018: Hubble Space Telescope captured image of a phenomenon called Einstein Ring. Einstein in his theory of general relativity, had suggested that a massive object would warp space and time. So, statement 3 is right. Hence we are left with correct answer "D": 1, 2 and 3 all correct.

QUESTION: 3

### In which of the following activities are Indian Remote Sensing (IRS) satellites used? 1. Assessment of crop productivity 2. Locating groundwater resources 3. Mineral exploration 4. Telecommunications 5. Traffic studies Select the correct answer using the code given below. [2015]

Solution:

Indian Remote Sensing (IRS) satellites are used in Assessment of crop productivity, Locating ground-water resources and Mineral exploration. This system was launched in 1979 and 1981. This system is used in agriculture, water resources, forestry and ecology, geology, marine fisheries and coastal management. It is the largest constellation of the remote sensing satellites.

QUESTION: 4

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.

[2013]

Solution:

The discovery of Higgs boson is important because it explains why sub atomic particles have mass.  According to the scientists, Higgs boson is the only particle which explains how the basic building blocks of matter interact.

QUESTION: 5

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?

[2013]

Solution:

Gravity is the feeble force among the four.

QUESTION: 6

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.

[2013]

Solution:

Thunder storms result from the rapid upward movement of warm, moist air. They can occur inside warm, moist air masses and at fronts. As the warm, moist air moves upward, it cools, condenses, and forms cumulonimbus clouds that can reach heights of over 20 km (12.45 miles). The thunderstorms are associated with the cumulonimbus clouds. These clouds normally form on warm sunny days but they can also be found on cold front. But this question is asking about the Thunder i.e. the sound produced. The lightning generates between 100 million and 1 billion volts of electricity and can heat the air to around 50K°F. The rapid expansion causes the shock waves.
Thunder happens because the lightning would heat the air at huge temperatures and the air expands so fast that it make a loud clap of thunder.

QUESTION: 7

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 below.

[2013]

Solution:

Formation of rainbow involves all dispersion, refraction and internal reflection.

QUESTION: 8

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?

[2013]

Solution:

Size of the Sun at dusk is an optical illusion because of atmospheric refraction. Colour of the sun appears yellow due to scattering whereas pure sunlight is white in colour. Twinkling of stars is an optical illusion. Air whirlpools make the stars twinkle.

QUESTION: 9

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

[2013]

Solution:

Ball bearings are used to reduce friction and friction is directly proportional to effective surface area. So if effective surface area is reduced then friction will also reduce.

QUESTION: 10

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?

[2012]

Solution:

1. It would be difficult to use a kerosene lamp
2. The blotting paper would fail to function
3. The big trees that we see around would not have grown on the Earth

QUESTION: 11

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?

[2012]

Solution:
QUESTION: 12

An artificial satellite orbiting around the Earth does not fall down. This is so because the attraction of Earth

[2011]

Solution:

An artificial satellite moving round the Earth in a circular orbit possesses an acceleration which is “constant” in magnitude but “changing in direction”. An artificial satellite revolves round the earth under centripetal acceleration. By the launch rocket, immediately before the satellite is established in the predetermined orbit, the speed given to it is 30, 000 km/hr. The speed must be great enough so gravity doesn’t bring the satellite back to Earth, but not so great that the satellite escapes gravity out into space. This means that the speed, which is provided by the rocket is the source of the centrifugal force, and the attraction of the earth holds it from moving away from this centrifugal force.

QUESTION: 13

Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such as orbit when:
1. The orbit is geosynchronous.
2. The orbit is circular.
3. The orbit lies in the plane of the earth’s equator.
4. The orbit is at an altitude of 22, 236.

Select the correct answer using the codes given below:

[2011]

Solution:

A geostationary orbit (or Geostationary Earth Orbit -GEO) is a geosynchronous orbit directly above the Earth's equator (0° latitude), with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. It is the part of space about 35, 786 km (22, 236 miles) above sea level, in the plane of the equator, where near geostationary orbits may be implemented.

QUESTION: 14

Consider the figure given below and answer the item that follows:

In the figure shown above, OP1 and OP2 are two plane mirrors kept perpendicular to each other. S is the direction of a beam of light falling on the mirror OP1. The direction of the reflected beam of light from the mirror OP2 will be:

[2011]

Solution:

In the above figure, dotted line shows the reflected beam of light from mirror OP2.

QUESTION: 15

The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason?

[2011]

Solution:

The anomalous expension of water as it cools from 4°C to 0°C means that the density of water is greatest at 4°C. So the ice that forms in cold weather forms at the top of the water (where the less dense coldest water gathers) and then acts as an insulating barrier preventing the water underneath from getting much colder (because heat cannot escape).

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