Question

why human beings cannot hear infrasonic and ultrasonic sound

Answer 1

Infrasonic sounds are less than 20Hz and ultrasonic sounds are greater than 20000Hz

Humans only have hearing range from 20Hz to 20,000 Hz.

The sounds that are infrasonic & ultrasonic are too hard for human ears to handle and interpret to the brain.

This is why we can't hear infrasonic or ultrasonic sounds.

I hope this helps.

Answer 2

Human ears have a range of 20Hz to 20000Hz. But infrasonic sounds has frequency less than 20 Hz and ultrasonic sounds have frequency more than 20000 Hz. So, we can not hear both of them.