Complete the following sentences —

(a) An average person can hear sounds 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.

Name the sounds of the frequencies given below —

(a) 10 Hz

(b) 100 Hz

(c) 1000 Hz

(d) 40 kHz

State the approximate speed of ultrasound in air.

Can you hear the sound produced due to vibrations of a seconds’ pendulum? Give reason.