Question

Which of the following statement is or are correct about longitudinal mechanical waves?
A) The longitudinal mechanical waves which lie in the frequency range 20 Hz to 20000 Hz are called audible or sound waves.
B) The longitudinal mechanical waves having frequencies less than 20 Hz are called infrasonic.
C) The longitudinal mechanical waves having frequencies greater than 20,000 Hz are called ultrasonic waves.
D) All of the above are correct

Answer 1

a) the longitudinal mechanical wavers which lie in the frequency range 20hz to20000hz are called audible or sound waves

Answer 2

All  the given options are correct  about longitudinal mechanical waves.

The correct option is (D) All of the above are correct.

Explanation:

The longitudinal mechanical waves which lie in the frequency range 20 Hz to 20000 Hz are called audible or sound waves. and having frequencies less than 20 Hz are called infrasonic and having frequencies greater than 20,000 Hz are called ultrasonic waves.