Question

what is ultrasonic sound and what is infrasonic sound

Answer 1

The sounds of frequency more than 20,000 Hz are called ultrasonic sounds .
The sounds of frequency less than 20 Hz are called infrasonic sounds .
None of these sounds are audible to normal man's ear

Answer 2

The sounds of frequency less than 20Hz are called infrasonics. Theinfrasonic sounds have below the lower limit of human hearing. Thesound of frequency more than 20,000Hz are called ultrasonics.ultrasonic sounds have a frequency above the upper limit of human hearing.