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Question
The echo of a sound is heard after 5 seconds. If the speed of sound in air be 342 m/s, calculate the distance of the reflecting surface.
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Solution
We have to calculate the distance between the reflecting surface and the observer.
Given: Time taken to hear the echo t = 5 s.
So time taken for sound to reach the reflecting surface (`t_r`) = `5/2` s
Speed of sound in air ν = 342 m/s
Therefore, distance of reflecting surface from the observer is
= `(v) xx (t_r)`
= `(342) xx (5/2)` m
= 855 m
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