Question

(i) Name the waves used for echo depth sounding.
(ii) Give one reason for their use for the above purpose.
(iii) Why are the waves mentioned by you not audible to us?

Answer 1

(i) The waves used for echo depth sounding are ultrasonic waves.

(ii) Ultrasonic waves are used for echo depth sounding because they can travel undeviated through long distances and can be confined to a narrow beam.

(iii) Ultrasonic waves are not audible to us because those waves have frequency more than 20,000 Hz and our audible range is between $20Hz$ to $20,000Hz$.