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HPSC HCS 2021 · Question 74 of 177

The depth of a sea can be determined by using SONAR. Consider the following statements about it: 1. It uses ultrasonic waves for the measurement of the depth of a sea. 2. The speed of ultrasonic waves in seawater is the same as that of sound in air. 3. Time taken by ultrasonic waves reflected from the bottom of the sea to reach the detector is used to measure the depth. Which of the above statement (s) is/are correct?

Physics

  1. A3 only
  2. B1 and 3 onlyCorrect
  3. C2 and 3 only
  4. D1,2 and 3 only

Answer: B. 1 and 3 only

Explanation

SONAR uses ultrasonic waves and depth is computed from the echo's travel time; sound travels much faster in seawater than in air.

Source: HPSC HCS (Ex.Br.) Prelims Paper-I (General Studies) held 12-Sep-2021 (exampyq/doorsteptutor compilation); answers per official HPSC answer key

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