Question

The echo receiver of a sonar attached to a ship, receives the echo from the bottom of sea 4 seconds after the ultrasonic waves were sent into the sea. If the speed of the sound in water is $1500\text{m/s}$, then what is the depth of the sea?

• A. $6000\text{m}$
• B. $3000\text{m}$
• C. $15000\text{m}$
• D. $3500\text{m}$

Answer 1

The correct option is B $3000\text{m}$

As the echo took 4 sec to reach the bottom and come again to surface of echo receiver.
Time taken to reach the sea bed is $\frac{4\text{sec}}{2}=2\text{sec}$
$\text{Distance = (speed)(time)}$
$=$ $1500\times 2$
$=$ $3000\text{m}$