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GeographyMediumAsked in: NDA · NDA-I 2023, GAT

Which of the following statements is/are correct ? 1. Hypocenter is the point on the surface of the Earth, nearest to the focus. 2. Velocity of earthquake waves is higher in denser materials. 3. P waves move faster and are the first to arrive at the surface of the Earth. Select the correct answer using the code given below :

  1. A.1 and 2
  2. B.2 and 3
  3. C.1 and 3
  4. D.3 only

Correct answer

B. 2 and 3

Explanation

The correct answer is B, 2 and 3. Statement 1 describes the epicentre, not the hypocentre; statements 2 and 3 are correct.

The hypocentre, or focus, is the point inside the Earth where the energy of an earthquake is released. The point on the surface directly above it, nearest to the focus, is the epicentre, so statement 1 is wrong. Earthquake waves change speed as they pass through layers of different density, and they travel faster through denser material, so statement 2 is right. P or primary waves are longitudinal waves that move through solids, liquids and gases and are the fastest, so they reach the surface and the seismograph first; statement 3 is right.

A is wrong: it includes the incorrect statement 1.

C is wrong: it also includes statement 1 and leaves out the correct statement 2.

D is wrong: statement 2 is also correct.

Exam tip: focus (hypocentre) is inside the Earth, the epicentre is on the surface above it; P waves arrive first, then S waves, then surface waves.

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.