Question

A ship moving at a speed of $1m{s}^{-1},$ emits a sonar signal directed towards the seabed and receives the signal after it has travelled $2m$. Calculate the approximate depth of seabed if the speed of sound in seawater is $1500m{s}^{-1}.$

• A. 1000 m
• B. 1500 m
• C. 2000 m
• D. 2500 m

Answer 1

The correct option is B 1500 m

Speed of ship = $1m{s}^{-1}$

Distance covered by ship between emitting and receiving the signal = 2 m

So, the time taken by the ship to cover 2 m = 2/1 = 2 s

In 2 seconds, the sonar signal was emitted from and received by the ship.

Speed of sound in seawater = $1500m{s}^{-1}$

So, in 2 seconds distance travelled by sound wave = $2s\times 1500m{s}^{-1}$= 3000 m.
3000 m is the total distance travelled by the sonar wave.
Hence, the approximate depth of seabed = 3000 / 2 = 1500 m.