Question

A ship sends ultrasonic waves and is detected after 10 seconds. The speed of the ultrasonic sound through seawater is 2 km/s. What is the depth of the sea?

• A. 10 km
• B. 5 km
• C. 15 km
• D. 20 km

Answer 1

The correct option is A 10 km

A ship sends ultrasonic waves and is detected after 10 seconds.
The speed of the ultrasonic wave through seawater = 2 km/s.
Let 'd' be the depth of the sea.
The distance travelled by the wave = 2$\times$d
$v=\frac{(2\times d)}{t}$
Where v = velocity, d = depth of the sea, t = time taken to detect the sound.
So, on substituting the values, we get
$2=\frac{(2\times d)}{10}$
$\to d=\frac{20}{2}$
$\to d=10km$