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GeographyMediumAsked in: CDS · CDS-I 2020, GK

In the Hadley cell thermal circulation, air rises up and finally descends at

  1. A.intertropical convergence zone
  2. B.doldrums
  3. C.subtropical high-pressure cells
  4. D.equatorial troughs

Correct answer

C. subtropical high-pressure cells

Explanation

The correct answer is C, subtropical high-pressure cells. In the Hadley cell, air rises near the equator and sinks at about 30 degrees latitude, in the subtropical high-pressure belts.

Strong heating near the equator makes air rise to the top of the troposphere. There it spreads towards the poles, cools and is turned by the Coriolis force, and around 30 degrees North and South it piles up and sinks. Sinking air warms and dries as it descends, which creates the subtropical highs, the horse latitudes and many of the world's hot deserts. From these highs, surface air flows back towards the equator as the trade winds, completing the cell. The Ferrel cell and the polar cell lie poleward of it.

A is wrong because the intertropical convergence zone is where the trade winds meet and the air rises, not where it sinks. B is wrong because the doldrums are the calm equatorial belt of rising air. D is wrong because the equatorial trough is another name for the same low-pressure belt of rising air.

Exam tip: Hadley cell: rises at the ITCZ, sinks at 30 degrees (subtropical high), returns as the trade winds.

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.