Question

What is infrasonic and ultrasonic waves ??

Answer 1

The sound waves of frequency below 20 hertz are known as infrasonic waves.
The sound waves of frequency more than 20000 hertz are known as ultrasonic waves.


hope it helps....

Answer 2

Infrasonic Waves :
The waves or vibrations which has frequency between 0 Hz to 20 Hz are known as infrasonic Waves.

Ultrasonic Waves :
The waves which has frequency greater than 20000 Hz are known as ultrasonic waves.