Question

4) What do you mean by infrasonic sound?​

Answer 1

infrasonic wave. Infrasonics, vibrational or stress waves in elastic media, having a frequency below those of sound waves that can be detected by the human ear—i.e., below 20 hertz. The range of frequencies extends down to geologic vibrations that complete one cycle in 100 seconds or longer.

Answer 2

Explanation:

Infrasound, sometimes referred to as low-frequency sound, describes sound waves with a frequency below the lower limit of audibility. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high.