Question

what are infra and ultrasonic sound....​

Answer 1

whose FREQUENCY is too low to be heard as sound by the human ear, i.e. below about 20 Hz is termed as infrasonic sound.

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing, I.e., 20 kHz.

Answer 2

Answer:

Infra sounds are sounds having frequency less than 20Hz

Explanation:

and Ultrasonic sounds are sounds having frequency more than 20,000 Hz