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  1. Class 9
  2. Chapter 12 Class 9 - Sound


NCERT Question 20 A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m? Distance of the object from submarine = 3625 m Time taken to receive the signal = 5 s Therefore, Time taken to reach the seabed = 5/2 s Let the speed of sound = v Now, Speed = (๐ท๐‘–๐‘ ๐‘ก๐‘Ž๐‘›๐‘๐‘’ )/(๐‘‡๐‘–๐‘š๐‘’ ) v = 3625/(5/2) v = (3625 ร— 2)/5 v = 725 ร— 2 v = 1450 m/s โˆด Speed of sound in water is 1450 m/s.

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.