Question

Sound waves with frequency less than$20Hz$ is _________.

• A. infrasonic
• B. ultrasonic
• C. audible
• D. supersonic

Answer 1

The correct option is A infrasonic

Human beings can only hear sounds whose frequency is ranging from $20Hz$ to $20kHz$. The sound waves below the frequency of $20Hz$ is called infrasonic sounds. The sound waves above the frequency of $20kHz$ is called ultrasonic sounds.