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 sound in water is 1500 m/s, then what is the depth of the sea​

Answer 1

Answer:

Given:

Echo is received after 4 secs.

Speed of sound in water = 1500 m/s

To find :

Depth of the sea

Concept :

Sound emitted from the under-surface of the ship traverses down, reaches the ocean-bed . There it undergoes reflection and travels upward and received by the ship.

So , the sound wave actually travels twice the depth of the ocean bed.

Calculation:

Let ocean bed depth be d .

But total distance travelled = 2d

\therefore \: 2d = speed \times time∴2d=speed×time

= > 2d = 1500 \times 4=>2d=1500×4

= > 2d = 6000 \: metres=>2d=6000metres

= > d = 3000 \: metres=>d=3000metres

So depth of the ocean is 3000 metres.

Importance of Sonar :

It helps to detect the depth of ocean floor.

It helps to detect any enemy submarines present near the ship.

It also helps in locating community of fishes in a particular region.