Why are the waves mentioned by you (ultrasonic waves) are not audible to us?

Q. (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?

Q. (a) What are infrasonic waves ? Name two animals which produce infrasonic waves.
(b) What are ultrasonic waves ? Name two animals which can produce ultrasonic waves.
(c) The audible range of frequencies of an average human ear is from 20 Hz to 20 kHz. Calculate the corresponding wavelengths. (Speed of sound in air is 344 ms^–1)

Q. What are the differences between infrasonic, audible and ultrasonic sound waves?

Q.

In SONAR we use :

(a) ultrasonic waves

(b) infrasonic waves

(c) radio waves

(d) audible sound waves