Question

A pendulum vibrates with a frequency of 1 Hz. The sound produced by it is:

• A. supersonic
• B. audible
• C. infrasonic
• D. ultrasonic

Answer 1

The correct option is C infrasonic

The audible frequency range for human ear is from 20Hz to 20000Hz , above 20000Hz , it is called ultrasonic and below 20Hz , it is infrasonic , as the given frequency (1Hz) is below 20Hz , so it is infrasonic .

Supersonic waves are related with the speed of sound in air , if any speed is greater than speed of sound , it is called supersonic .