Question

What are the sound waves of frequencies less than 20 Hz called :
(a) Infrasonic
(b) Ultrasonic
(c) Sonar
(d) None of these​

Answer 1

Answer:

hey mate

option a is correct answer

followme guys

mark this answer as a branliest answer

Answer 2

The correct answer is option (a) Infrasonic.

• The sound frequency of less than 20 Hz is called Infrasonic.

• Infrasound is sometimes called low-frequency sound, identifying sound waves with a frequency below the human limit (frequency 20 Hz). Hearing gradually reduces sensitivity gradually as frequency decreases, so for people to see infrasound, sound pressure should be high enough. The ear is a key to hearing low-pitched sounds, but when it is too loud, it is possible to hear complex vibrations in various parts of the body.