Chapter 11 Sound Questions-06
Question
1. An echo is heard in $3 s$. What is the distance of the reflecting surface from the source, given that the speed of sound is $342 m s^{-1}$ ?
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Answer
Speed of sound $(v)=342 ms^{-1}$
Echo returns in time $(t)=3 s$
Distance travelled by sound $=v \times t=342 \times 3=1026 m$
In the given interval of time, sound must travel a distance which is twice the distance between the reflecting surface and the source.
Therefore, the distance of the reflecting surface from the source $=1026 / 2=513 m$
