Question

A sound produced on the surface of a lake takes 4.5 s to reach a boat man. How much time in seconds will it take to reach a diver inside water at the same distance if speed of sound in water is 4:5 times the speed of sound in air?

Answer 1

Given, $V_{water}:V_{air}=4.5,t_{air}=4.5s,t_{water}=?$

$fromrelation{V}_{air}=\frac{d}{t_{air}}and{V}_{water}=\frac{d}{t_{water}}$

$or{V}_{air}\times t_{air}{=V}_{water}\times t_{water}$

$t_{water}=\frac{V_{air}}{V_{water}}\times t_{air}=\frac{1}{4.5}\times 4.5s=1s$