Physics - Sound Wave Question with Solution | TestHub

Time taken for $60$ claps is $2$ minutes $=120\text{s}$.

Time interval between two consecutive claps is $T=\frac{120}{60}=2\text{s}$.

Let the distance of the boy from the wall be $x$. The sound travels a distance of $2x$ (to the wall and back) to form an echo.

Time taken for the echo to return is $t=\frac{2x}{v}$.

Since each clap coincides with the echo of the previous one, the time for the echo to return equals the time interval between claps, so $t=T$.

$\frac{2x}{340}=2$

$2x=680$

$x=340\text{m}$

Answer: $340\text{m}$