Question

Question 1
An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is $342m{s}^{-1}$?

Answer 1

Speed of sound, $V=342m{s}^{-1}$
Echo returns in time, t = 3s
Distance travelled by sound = $V\times t=342\times 3=1026m$
In the given time interval, sound has to travel a distance that is twice the distance of the reflecting surface and the source.
Hence, the distance of the reflecting surface from the source = $\frac{1026}{2}m=513m.$