Question

What is 'SONAR' ? State the principle on which it is based.

Answer 1

Sonar (SOund Navigation And Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.
The echolocation principle is used in SONAR.
Echolocation is the ability to locate objects by bouncing sound waves off of them, and then measuring the time taken for an echo to return, and calculating the direction the echo came from. These sound waves are very high-pitched, and most humans are unable to hear them.