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The Amplitude of a Wave

Last updated date: 04th Mar 2024
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Introduction to Waves

Waves are an integral part of our daily lives as well as physics. Scientists conduct several experiments on the basis of the properties of waves. The waves include several factors like their amplitude, wavelength, speed, etc.

One can learn how to analyse different factors of the wave through analysis of their amplitude, wavelength and speed. Such factors determine the difference between several waves and hence make them unique. Some of such waves can help in the distribution of light and sound to different places.

Hence, Let us learn about each of its factors in detail and understand its properties and factors affecting the amplitude of the wave.

Wave Definition and How to Graph it?

A wave is a disturbance that travels from one point to another in a medium. Waves can travel in air and water but they do not exist in a vacuum. There are properties shown by a wave-like wave amplitude, speed, frequency, wavelength, phase of a wave, and period.

When we draw a wave on the graph, we draw it travelling through time or distance. The Y or the vertical axis shows the amplitude of a wave while the X or the horizontal axis shows the time or distance through which the wave travelled. 

Amplitude of a wave

Amplitude of a Wave

Characteristics of Wave

  • The highest point of the wave is called the crest while the lowest point of the wave is called a trough.

  • The line which is passing through the centre of the wave shows the resting position of the medium when no waves might be passing through it. 

The Amplitude of A Wave

The amplitude of a wave can be described as the measure of the displacement of the wave from its resting position. The amplitude can be calculated by observing the graph of a wave and measuring its height from the resting position.

The strength and intensity of a wave are measured through the wave. Similarly, the loudness of sound is measured by the amplitude of a sound wave. Also, the energy of the wave is considered directly proportional to the amplitude of the wave. 



The Wavelength of A Wave

Distance between two corresponding points on continuous cycles of a wave is considered to be the wavelength of a wave. The wavelength can be measured through two crests or two troughs of the wave. 

The Greek letter Lambda (𝛌) is used to denote the wavelength of a wave in general. 

Periods and Frequency of a Wave

The number of times a wave cycles per second is called the frequency of a wave. The measurement of frequency is done through cycles per second or through Hertz (Hz). Generally, the ‘ f ’ letter is used to denote frequency.

The time taken in order to complete one vibration is known as the time period. A period is measured through time units, generally in seconds. It is represented through the uppercase letter ‘T’.

Time period and Frequency are somewhat related to each other. Frequency and time period are considered to be inversely proportional to each other and are reciprocals to each other.

\[ \text { period }= 1 \text { frequency } \text { or } T=1 f \]

\[\text { frequency } = 1 \text { period } \text { or } f=1 T \]

Speed or Velocity of a Wave

The speed of propagation of any wave is considered an important factor, it determines how fast a wave is moving through the disturbances. The speed of the wave is somewhat dependent on the medium it travels through. The speed of the wave varies in different mediums, it changes depending upon the medium it travels through.

Velocity = Frequency x Wavelength


V = F x λ

The velocity or speed of the wave is calculated by multiplying the frequency by wavelength. It is represented through the letter ‘v’.

For Example: Let the frequency of the wave be $5hz$ and the wavelength is $4m$. Then calculate the velocity of the wave. 

Ans. Since, Velocity = Frequency x Wavelength

Then, velocity of wave = 5 x 4 = 20 $\mathrm{~m} \mathrm{s}$


The waves are considered an important element of the physical sciences and several of our daily life habits are successful only due to the presence of waves in our environment. Several parts of waves like the amplitude of a wave have their own significance and help us calculate different parts of the wave. 

FAQs on The Amplitude of a Wave

1. Explain the difference between a travelling wave and a standing wave.

Waves are an integral part of physics and have several attributes present in them such as amplitude and frequency. Hence, there can be several aspects to a wave that make them significantly different to each other. Period disturbances that move through different mediums like air, water, etc and move from one point to another are known as travelling waves while the waves which oscillate within a plane without transferring energy are known as standing waves. This is the basic difference between a travelling wave and a standing wave.

2. Write down the attributes of simple harmonic motion and name three characteristics of a wave.

Simple harmonic motion occurs when periodic and repeated motion consists of constant amplitude and frequency. If an oscillation satisfies the following two conditions, it is said to follow simple harmonic motion: Every time there is acceleration, there is also a displacement from the equilibrium position. The distance between the equilibrium position and the acceleration is inversely proportional. In a basic harmonic motion, the particle's acceleration is geared toward its mean location and directly proportional to its displacement.

Properties such as the amplitude of a wave, frequency, and length of the wave. 

3. What increases the amplitude of a wave?

The increase in the amplitude of a wave is observed when the length between the peak and bottom trough increases. To increase the amplitude of a wave, we can increase the movement or distance. For sound waves, if we increase the volume, it automatically increases the amplitude of a wave.