Question

what is sonar and its applications

Answer 1

Sonar (originally an acronym for 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.

Answer 2

SONAR is used in ships for measuring the depth of the sea..and distace between obstacles

its like infrared when the signal came bounce back by reflecting from the surface ..it able to detect the object and its size.distace etc..

Sonar application:
used for underwater applications
like ship and submarines