Question

A boy shouts loudly into an empty well that is 33m deep. After how long will he hear the echo? (Speed of sound in air 330 m/s)

Answer 1

Explanation:

ANSWER

Let d be the distance of body from water level in well (depth of water level) , therefore total distance travelled by sound wave , =2d , as the wave comes back after reflection so the distance will be doubled .

Now given , v=340m/s,t=0.4s ,

therefore , by , total distance =velocity × total time

2d=v×t ,

or d=v×t/2=340×0.4/2=68m