Question

A girl blew a whistle while standing in front of a cliff. She heard an echo after $4s$. Find the distance of the cliff from the boy if velocity of sound in air is $332m{s}^{-1}$

• A. $332m$
• B. $664m$
• C. $166m$
• D. $1328m$

Answer 1

The correct option is B $664m$

Time taken by the sound to go from the boy to the cliff, $t=\frac{4}{2}s=2s$

Speed of sound in air, $v=332m{s}^{-1}$

So, distance of the cliff from the boy, $s=v\times t=332\times 2m=664m$.