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GeographyMediumAsked in: NDA · NDA-I 2026, GAT

Consider the following pairs : Layers of Atmosphere — Characteristics I. Troposphere — Absorbs ultraviolet radiation II. Stratosphere — Changes in weather and climate III. Mesosphere — Reflects radio waves back to the Earth How many of the pairs given above are correctly matched?

  1. A.None
  2. B.One
  3. C.Two
  4. D.All the three

Correct answer

A. None

Explanation

The correct answer is A, None. Each characteristic in the list belongs to a different layer from the one it is paired with.

Ultraviolet radiation is absorbed by the ozone layer, which lies in the stratosphere, roughly 15 to 35 km above the Earth. Weather and climate changes happen in the troposphere, the lowest layer, which holds almost all the water vapour, clouds and dust. Radio waves are reflected back to the Earth by the ionosphere, the layer of charged particles above the mesosphere, roughly from 80 km upwards. The mesosphere itself is the coldest layer, where temperature falls to about minus 100°C and meteors burn up.

B is wrong because not even one pair is correct: the troposphere does not absorb ultraviolet rays. C is wrong because the stratosphere is calm and free of weather. D is wrong because the mesosphere does not reflect radio waves.

Exam tip: weather in the troposphere, ozone in the stratosphere, meteors in the mesosphere, radio waves in the ionosphere.

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.