Question

(a) What is sonar ? Explain its use.
(b) A sonar station picks up a return signal after 3 seconds. How far away is the object ? (Speed of sound in water = 1440 m/s).

Answer 1

(a) SONAR is an acronym for SOund Navigation And Ranging. Sonar is an apparatus that is used to find the depth of a sea or to locate the underwater things like shoals of fish, shipwrecks, and enemy submarines.

(b)We have to calculate the depth using a sonar signal.
Given: Time taken to listen to the return signal t = 3 s
So time taken to reach the depth $\left(t_{\mathrm{D}}\right)=\frac{3}{2}\mathrm{s}$
Speed of sound in water ν = 1,440 m/s
So the depth can be calculated as
= ν × t_D
= 1440 × 1.5 m
= 2160 m