Question

sound having frequency less than 20 hz are called .
a. supersonic
b. ultrasonic.
c. sonar
d. infrasonic.​

Answer 1

Answer:

d) Infrasonic

Explanation:

Sound at 20-200 Hz is called low-frequency sound, while for sound below 20 Hz the term infrasound is used.

Answer 2

Answer:

Ultrasonic has frequency less than 20 hz