Question

The speed of sound in water is 1500 metres per second. How far away from an under-sea rock should a deep sea diver be so that he can hear his own echo ?

Answer 1

The speed of sound in water = 1500 m/s


Minimum time of sound for the echo to be heard = 0.1 s

Minimum distance =$v\times \frac{t}{2}=1500\times \frac{0.1}{2}$=75m