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The Universe

📆 October 21, 2024

Total Questions: 51

1. The 'Black Hole' was first made known by [U.P.P.C.S. (Pre) 2015]

Correct Answer: (c) S. Chandrashekhar
Solution:Subhramanyam Chandrashekhar was a great scientist and Nobel Prize winner who gave details on black hole theory. He is known for Chandrashekhar limit which showed that there is a maximum mass which is supported against gravity by pressure made up of electrons and atomic nuclei (The value of this limit is about 1.44 times of solar Mass) which was derived by Chandrashekhar in 1931. He was awarded Nobel Prize for Physics jointly with W.A. Fowler in 1983.

2. Information about 'Black Hole' was first provided by- [U.P.P.C.S. (Mains) 2016]

Correct Answer: (a) S. Chandrashekhar
Solution:From the given above option the information about 'Black Hole' was presented by Dr. S. Chandrashekhar. On 11 January, 1935 he presented a research paper in Royal Astronomical Society of London and propounded that a white dwarf star turns into a Black Hole after attaining certain mass. He was jointly awarded Nobel Prize for Physics in 1983 with W.A. Fowler.

3. Assertion (A): A black hole is an astronomical entity that cannot be seen by telescope. [U.P.P.C.S.(Pre) 2003, U.P.P.C.S.(Pre) 2001]

Reason (R) : The gravitational field on a black hole is so strong that it does not allow even light to escape.

In the context of the above statements, which one of the following is correct:

 

Correct Answer: (a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
Solution:Assertion (A) and Reason (R) both are true and Reason (R) explains Assertion (A) properly. It is not possible to observe a black hole directly with the help of a telescope. The intense gravitational field of black hole due to the high density does not allow any type of radiation. Even light rays cannot escape from this. The presence of black hole is ascertained by the behaviour of stars, gases and masses near it with the help of space telescope.

4. A 'black hole' is a body in space which does not allow any type of radiation to come out. This property is due to its - [I.A.S. (Pre) 2000]

Correct Answer: (c) High density
Solution:

Assertion (A) and Reason (R) both are true and Reason (R) explains Assertion (A) properly. It is not possible to observe a black hole directly with the help of a telescope. The intense gravitational field of black hole due to the high density does not allow any type of radiation. Even light rays cannot escape from this. The presence of black hole is ascertained by the behaviour of stars, gases and masses near it with the help of space telescope.

5. How many constellations are in our space? [44th B.P.S.C. (Pre) 2000]

Correct Answer: (b) 88
Solution:

According to the International Astronomical Union, there are 88 constellations in the sky. Most of these imaginary patterns can be seen from the southern hemisphere. It will take a full year to get a glimpse of all the constellations.

6. Which one of the following is not an Astronomical object? [I.A.S. (Pre) 1993]

Correct Answer: (b) Brittle star
Solution:

Brittle star is not an astronomical object. Brittle stars are echinoderms in the class ophiuroidea closely related to starfish. These are aquatic creatures and crawl on the sea floor, while Pulsar is celestial body emitting very regular pulses of radio waves. Quasar is an astronomical object of very high luminosity found in the centres of some galaxies at a distance of billions of light-years. A black hole is also a cosmic body of extremely intense gravity from which nothing (even light) can escape and formed by the death of a massive star. Thus, option (b) is the correct answer.

7. Which one of the following is NOT found in space? [U.P.P.C.S. (Pre) 1996]

Correct Answer: (b) Brittle Star
Solution:Pulsar, Black hole and Quasar are found in space while Brittle Star is echinoderms closely related to Starfish. Hence Brittle Star is related to sea, not space.

8. A group of stars arranged in a particular shape, is called- [U.P.P.C.S. (Pre) 2013]

Correct Answer: (c) Constellation
Solution:A constellation is a group of stars that appear to form a recognizable pattern or shape in the night sky when viewed from Earth.Some well-known constellations include Orion, Ursa Major. The ancient people named many of these recognizable constellations after the objects or animals they resembled. They built stories around them too. For example, the constellation Perseus, Andromeda, Cetus, Cassiopeia and Pegasus are all linked to the mythology of the Greeks. Common constellation names are similar across cultures such as Pisces - the fish in Greek is also called Meena (also meaning fish) in Sanskrit.

9. Hubble space telescope has captured, for the first time, detailed image of the surface of a distant star. Name of the star: [U.P.P.C.S. (Pre) 1995]

Correct Answer: (c) Betelgeuse
Solution:Betelgeuse is second-brightest star in the Constellation of Orion. It is at a distance of about 700 light year from the Earth. It was the second star after Sun, whose image had been captured.

10. Consider the following Statements - A person in spacecraft situated at the mid of earth and Sun will see that - [I.A.S. (Pre) 1996]

1. Sky is black

2. Stars do not twinkle

3. The temperature outside the spacecraft is more than that of the earth surface.

Which of the following is true?

Correct Answer: (b) 1 and 2
Solution:Due to the absence of atmosphere in space, the sky appears black and stars do not twinkle. Twinkling of stars is caused by the passing of light through different layers of turbulent atmosphere similarly it is due to the atmosphere that light scatters to let us see the blue sky. Outside the spacecraft (in space) the temperature is 2.7 Kelvin (- 270.45°C) which is much less than temperature of Earth surface. So, statement 3 is wrong.
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