# Amplitude of a Wave

A sound is a form of energy that is produced by vibrating bodies. It requires a medium for the propagation. It cannot propagate in a vacuum as there will be no material to transfer sound waves. Sound cannot be produced without the vibration of objects. The back and forth motion of an object are known as sound vibration. This to and fro motion or back and forth motion is also known as oscillatory motion. The regular rhythmic back and forth movement are referred to as oscillation. Some of the quantities that are used to explain sound are period, frequency and amplitude. They are described below:

#### Period of sound

A period can be said to be the time taken to do something. If an event occurs repeatedly then the event is said to be periodic. The time taken by the periodic event to repeat itself is known as the period. The time taken by the particle to complete one vibration cycle is the time period for that particle.

Period = 1/Frequency

#### Frequency of Sound

The number of oscillations per second is known as the frequency of oscillation. Its unit is hertz and is denoted by Hz. The frequency of a wave in general means how frequently the particles of a medium vibrate when a wave moves through the medium.

Frequency = 1/Period

#### Amplitude of sound

The amplitude of a sound wave is the measure of the height of the wave. The amplitude of a sound wave can be defined as the loudness or the amount of maximum displacement of vibrating particles of the medium from their mean position when the sound is produced. It is the distance between crest or trough and the mean position of the wave.

Loudness is directly proportional to the amplitude of the sound. If the amplitude of a sound wave is large then the loudness of sound will be more. If the amplitude is small then the sound will be feeble.