Question

ii) Ultrasound has frequency less than 20 Hz.​

Answer 1

Answer:

Ultrasonic and Infrasonic sound waves are waves that are not audible to human beings. That is known as the audible range. ... waves that have frequency less than 20 hz is known as infrasonic waves and more than 20khz are called ultra sonic waves. The sound which frequency is below 20 hertz is called infrasonic sound