Question

Q4. 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 in sea.
if speed of sound in water is 1500m/s then dept of sea is?(please explain In detail)
A)6000m
B)3000m
C)15000m
D)3500m​

Answer 1

Answer : (B) 3000m

Explanation :

As The echo took 4s to reach the bottom and come again to surface of the echo-receiver.

Then the time taken to reach the sea bed is

4s/2= 2s

Formula of calculating Distance ,speed and Time is

Distance = Speed × Time

Dept of sea bed = 1500 × 2

= 3000m

Answer 2

Given:

• Echo was received after 4 seconds.
• Speed of sound in water = 1500 m/s.

To find:

• Depth of the sea.

Concept:

(☆Refer to the attachment.)

Ultrasonic sound waves are used to measure the depth of the sea. For this purpose, frequency of more than 50kHz is used.

SONAR (SOund Navigation And Ranging) is an equipment used to find underwater objects with the help of sound waves.

Here, the ship has a transmitter and a detector. The transmitter sends the ultrasonic sound waves in the water. When this sound wave is reflected by the object, then the detector detects it.

Solution:

We know that,

2d = v×t

Where,

d = distance (It is written 2d in the formula because the sound travels the same distance two times, first when the transmitter sends it to the object, second when the detector receives it.)

v = speed

t = time

Substitute the values in the formula,

2d = v×t

2d = 1500×4

2d = 6000

$\sf {d= \dfrac {6000}{2}}$

$\boxed {\bf {\orange {d = 3000m}}}$

Final answer:

Depth of the sea is 3000 m.

Therefore, option b) 3000 m is correct answer. ✔