Question

In a sonar, ultrasonic waves are sent into the sea water and the reflected waves from a sunken ship are received after 2.0 s. If the velocity of waves in sea water is $1450{ms}^{-1}$​, find the depth of sunken ship.

• A. $2900\text{m}$
• B. $1450\text{m}$
• C. $2800\text{m}$
• D. $3000\text{m}$

Answer 1

The correct option is B $1450\text{m}$

Let $v$ be the velocity of the waves formed, $t$ be the time taken and $d$ be the depth of the sunken ship.
Given, time taken for the wave to move towards the sunken ship, get reflected and reach back to the source, $2t=2s\Rightarrow t=\frac{2}{2}=1s$
Velocity of waves formed, $v=1450m{s}^{-1}$,
Depth of sunken ship, $d=speed\times time=v\times t$
$\Rightarrow d=1450\times 1$
$\Rightarrow$ $d=1450m$
$\therefore$The depth of the sunken ship is 1450 m.