Question

An echo returned in $3S$. What is the distance of the reflecting surface from the source, given that the speed of sound is $342ms$?

Answer 1

Echo returns in $3S$. Therefore time taken by sound to travel from the source to the reflecting surface

$t=\frac{3}{2}=1.5S$

Speed $v=342m{s}^{-1}$

$\therefore$ Distance of reflecting surface from the source $=Speed\times Time$

$=342\times 1.5=513m$.