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 stands for Sound, Navigation and Ranging. It is a device used to measure distance, direction, and speed of underwater objects. It has a transmitter and detector near its base. The transmitter transmits ultrasonic signals which get reflected by various underwater objects. These are received by the detector which can convert these waves into appropriate electrical signals and give us the required information.

(b) Time of echo = 3 s

speed of sound = 1440 m/s

Distance = $v\times \frac{t}{2}=1440\times \frac{3}{2}$=2160m