UPSC Physical Geography – Chapter 1: The Universe, the Solar System and the Earth (22 MCQs)

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UPSC Physical Geography – Chapter 1: The Universe, the Solar System and the Earth (22 MCQs) – 22 questions, subject: Geography. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

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1.  

The evidence that the universe is expanding was first given by:

Correct Answer: B [Edwin Hubble]

Explanation:

1920s.

2.  

According to NCERT, the Big Bang took place about:

Correct Answer: A [13.7 billion years ago]

Explanation:

NCERT dates the Big Bang to about 13.7 billion years ago; modern measurements refine it to about 13.8 billion years.

3.  

The nebular hypothesis of the origin of the solar system was first put forward by:

Correct Answer: C [Kant]

Explanation:

1755.

4.  

A light year is a unit of:

Correct Answer: C [distance]

Explanation:

A light year is the distance light travels in one year at about 3 lakh km per second, nearly 9.46 lakh crore km.

5.  

Which planet is the hottest in the solar system?

Correct Answer: B [Venus]

Explanation:

thick carbon-dioxide atmosphere.

6.  

The least dense planet of the solar system is:

Correct Answer: D [Saturn]

Explanation:

Saturn is so light for its size that its average density is less than that of water, the lowest of all planets.

7.  

Pluto was reclassified as a dwarf planet by the IAU in:

Correct Answer: C [2006]

Explanation:

The IAU's 2006 definition of a planet required clearing its orbit; Pluto failed and became a dwarf planet, leaving eight planets.

8.  

The shape of the Earth is best described as:

Correct Answer: D [a geoid]

Explanation:

The Earth is flattened at the poles and bulges at the equator, a unique shape called a geoid, close to an oblate spheroid.

9.  

The accepted explanation of the origin of the Moon is the:

Correct Answer: D [giant-impact theory]

Explanation:

A Mars-sized body struck the young Earth and the debris formed the Moon about 4.44 billion years ago (NCERT).

10.  

Consider the following statements:

1. Sunspots are cooler regions of the Sun's surface.
2. The number of sunspots varies in a cycle of about 11 years.
3. Sunspots are caused by the Moon's gravity.

Which of the statements given above is/are correct?

Correct Answer: B [1 and 2 only]

Explanation:

Sunspots are cooler, darker regions caused by strong magnetic fields, and their number varies in a cycle of about 11 years.

11.  

Assertion (A): Free oxygen was almost absent in the Earth's early atmosphere.

Reason (R): Oxygen accumulated in the atmosphere only after organisms began photosynthesis.

Correct Answer: A [Both A and R are true, and R is the correct explanation of A]

Explanation:

Free oxygen was scarce early because it built up only after photosynthesis began, so R directly explains A.

12.  

The process by which heavier materials sank to the centre of the Earth is called:

Correct Answer: A [differentiation]

Explanation:

In differentiation, heavier materials such as iron sank to the centre and lighter ones rose, forming crust, mantle and core.

13.  

Which of the following is NOT an effect of a severe solar storm on the Earth?

Correct Answer: D [tsunamis in equatorial seas]

Explanation:

(d) Correct (Prelims 2022).

14.  

The planet that rotates on its side, with its axis tilted about 98°, is:

Correct Answer: C [Uranus]

Explanation:

Uranus's axis is tilted about 98°, so it rotates almost on its side as it orbits the Sun.

15.  

Dinosaurs became extinct at the end of the:

Correct Answer: B [Mesozoic era]

Explanation:

about 66 million years ago.

16.  

The magnetosphere of the Earth is generated mainly by:

Correct Answer: A [the liquid outer core]

Explanation:

Convection of molten iron in the liquid outer core acts as a dynamo, generating the magnetic field that forms the magnetosphere.

17.  

Arrange the following in chronological order:

1. IAU reclassifies Pluto
2. Kant's nebular hypothesis
3. Chandrayaan-3 lands on the Moon
4. Hubble shows the universe is expanding

Select the correct answer using the code given below:

Correct Answer: C [2-4-1-3]

Explanation:

1755, 1920s, 2006, 2023.

18.  

India's Aditya-L1 mission studies:

Correct Answer: B [the Sun]

Explanation:

Aditya-L1, launched in September 2023, observes the Sun's corona, flares and solar wind from a halo orbit around L1.

19.  

Sunlight takes about how long to reach the Earth?

Correct Answer: A [8 minutes 20 seconds]

Explanation:

At about 3 lakh km per second, light covers the 150 million km Sun–Earth distance in about 500 seconds.

20.  

The Kodaikanal Solar Observatory is known for:

Correct Answer: B [one of the longest records of sunspot observations]

Explanation:

Founded in 1899 and now run by the Indian Institute of Astrophysics, it holds over a century of daily sunspot records.

21.  
UPSC Prelims 2022

If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth?

1. GPS and navigation systems could fail.
2. Tsunamis could occur at equatorial regions.
3. Power grids could be damaged.
4. Intense auroras could occur over much of the Earth.
5. Forest fires could take place over much of the planet.
6. Orbits of the satellites could be disturbed.
7. Shortwave radio communication of the aircraft flying over polar regions could be interrupted.

Select the correct answer using the code given below:

Correct Answer: C [1, 3, 4, 6 and 7 only]

Explanation:

solar storms do not cause tsunamis or forest fires.

22.  
UPSC Prelims 2018

Consider the following statements:

1. The Earth's magnetic field has reversed every few hundred thousand years.
2. When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide.
3. When living organisms originated, they modified the early atmosphere of the Earth.

Which of the statements given above is/are correct?

Correct Answer: C [1 and 3 only]

Explanation:

the early atmosphere had almost no free oxygen.

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