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GeographyMediumAsked in: NDA · NDA-I 2023, GAT

Which one of the following is the correct sequence of arrangement of the given planets in descending order of their density (in gm/cm3)?

  1. A.Earth > Jupiter > Venus > Saturn
  2. B.Jupiter > Earth > Saturn > Venus
  3. C.Earth > Venus > Jupiter > Saturn
  4. D.Earth > Venus > Saturn > Jupiter

Correct answer

C. Earth > Venus > Jupiter > Saturn

Explanation

The correct answer is C, Earth > Venus > Jupiter > Saturn. The rocky planets are dense, the gas giants are light, and Saturn is the least dense planet of all.

Earth is the densest planet in the Solar System at about 5.5 g/cm³, with Venus close behind at about 5.2 g/cm³; both are made of rock and metal. Jupiter, a giant made mostly of hydrogen and helium, has a density of only about 1.3 g/cm³. Saturn's density, about 0.7 g/cm³, is less than that of water, so in theory it would float in a large enough ocean.

A is wrong: Venus is far denser than Jupiter, so it cannot come after it.

B is wrong: Jupiter is not denser than Earth, and Saturn is not denser than Venus.

D is wrong: Jupiter is denser than Saturn, so Saturn must come last.

Exam tip: the densest planet is Earth and the least dense is Saturn, which is lighter than water.

Practice Questions

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Q2.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements is/are correct? 1. Himalayan rivers have their origin in the snow-covered areas, hence are dry in winter season. 2. Rivers of the Peninsular Plateau have reached maturity. 3. Himalayan rivers depict all the three stages of normal cycle of erosion. Select the correct answer using the code given below.

  1. A.2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: C. 2 and 3 only

Himalayan rivers are perennial, so statement 1 is wrong, while statements 2 and 3 are correct. Himalayan rivers such as the Ganga, Indus and Brahmaputra rise from glaciers and snowfields and also get monsoon rain, so they flow all year round, including in winter.

Q3.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements related to latitude are true? 1. Rainfall, temperature and vegetation vary with latitude. 2. The difference between the longest day and the shortest day increases with latitude. 3. Indira Point is located approximately at 6°45' N latitude. Select the correct answer using the code given below.

  1. A.1 and 2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: D. 1, 2 and 3

All three statements about latitude are true. Latitude decides how directly the Sun's rays strike a place, so temperature, rainfall and the type of vegetation change from the equator towards the poles, from hot, wet rainforests to cold tundra.

Q4.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following lakes is/are situated in Ladakh? 1. Tso Kar 2. Pangong Tso 3. Tsomgo 4. Tso Moriri Select the correct answer using the code given below.

  1. A.1 only
  2. B.2 and 3
  3. C.1, 2 and 4
  4. D.2 and 4 only
Show answer
Correct answer: C. 1, 2 and 4

Tso Kar, Pangong Tso and Tso Moriri are high-altitude lakes of Ladakh, while Tsomgo lies in Sikkim. Pangong Tso, at about 4,350 metres, is a long, narrow lake that stretches from Ladakh into Tibet, and most of its length lies on the Chinese side.