Question

explain Sonar and how it can be used to determine the depth of the sea

Answer 1

Sonar is an equipment to measure the depth of the sea...
in it what actually is done is that sound is sent in the sea and it's echo is observed. the time taken by the echo is calculated and according to that the depth is calculated......

Answer 2

Sonar means SOund Navigation And Ranging. It is a device used to measure depth of the sea or other big objects under the water. It uses ultrasonic waves and returns. By this they can calculate the depth of the sea.