Question

defination of infrasonic wave

Answer 1

Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. 

it will surely help you don't worry

Answer 2

Sound is only audible to the average human

ear if the frequencies lie between 20Hz and

20kHz. The actual range varies from person

to person. Sound waves with frequencies less

than 20Hz are called Infrasonic  or subsonic

and those with frequencies above 20kHz are called Ultrasonic.


Hope it will help you

Thanks