Infrasonic frequency range is

1. Below 20 Hz

2. 20 Hz to 20kHz

3. Above 20 kHz

4. No limit

Q.

Complete the following sentences :

(a) An average person can hear sound of frequencies in the range ___ to ___.

(b) Ultrasound is of frequency ___ .

(c) Infrasonic sound is of frequency ___ .

(d) Bats can produce and hear ___ sound.

(e) Elephants produce ___ sound.

Q. Infrasonic sound is of frequency

Q. (a) What are infrasonic waves ? Name two animals which produce infrasonic waves.
(b) What are ultrasonic waves ? Name two animals which can produce ultrasonic waves.
(c) The audible range of frequencies of an average human ear is from 20 Hz to 20 kHz. Calculate the corresponding wavelengths. (Speed of sound in air is 344 ms^–1)

Q. Which has larger frequency – infrasonic sound or ultrasonic sound?