Question

Explain ultrasonic and infrasonic sound

Answer 1

The sound frequency above 20000 Hz or 20 KHz is know as ultrasonic sound
The sound frequency below 20 Hz is know as infrasonic sound

Answer 2

$\Large{\underline{\underline{\bf{Solution :}}}}$

★ Ultrasonic waves :

A longitudinal wave whose frequency is above the upper limit of audible range i.e. 20 kHz, is called ultrasonic wave. It is generated by very small sources. Example : Quartz crystal

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★ Infrasonic wave :

A longitudinal elastic wave whose frequency is below the audible range i.e. 20 Hz, is called an infrasonic wave. It is generally generated by a large source. Example : Earthquake.