Question

The frequency of sound is 500 Hz. How many times it vibrates in a minute.
$\text{A}\text{. 30000}$
$\text{B}\text{. 300}$
$\text{C}\text{. 30}$
$\text{D}\text{. 8}\text{.33}$

Answer 1

Frequency is defined as the number of vibrations per unit second by a body in periodic motion. It has SI unit Hertz (Hz). One Hz is equal to one vibration per unit second. To solve this question we will have to change the unit of frequency from Hz to vibrations per minute.

Formula used:
Frequency $f=\dfrac{1}{T}$

Complete step by step answer:
Frequency of a wave is defined as the number of waves passing through a fixed point in unit time. In other words, it is the number of vibrations per unit second. Its SI unit is Hertz. One Hz means one vibration/cycle in one second.
Frequency of a particle in periodic motion of time period T is
$f=\dfrac{1}{T}$ Vibrations per second
Sound is a wave produced because of back and forth vibrations of the particles of the medium through which the sound wave is moving. We are given that sound has frequency of 500 Hz, which means particles of medium are vibrating with 500 vibrations in one second.
Mathematically,
$f=500\text{ vibrations/second}$
Therefore vibrations in one minute will be
$f=500\times 60s$
$f=30000$Vibrations/minute
Hence, option A is correct.
Additional Information: In a wave, the distance between adjacent crests or adjacent troughs is known as wavelength. Wavelength has SI unit m.
The product of wavelength and frequency of a wave in a medium is equal to velocity of the wave.

Note:
A vibrating object like a tuning fork or human voice causes a sound wave. Sound waves are longitudinal waves because in sound waves, particles vibrate to and fro about their mean position in the direction of propagation of waves which is the property of longitudinal waves. The term frequency related to sound waves indicates how often the particle vibrates when the wave passes through the medium.