Waves Class 11 Notes

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Waves Class 11 Notes

From Gravitation and Thermal Properties to Kinetic Theory of Gases and Laws of Motion, the Physics syllabus for class 11th is structured not only to build a strong foundation of the subject but also to prepare students for various international and government exams after 12th Science. Though all are equally important, Waves is one of the fundamental topics of Physics and one needs to develop a stronghold over its concepts. So, to make your work easy, here is a blog that elucidates upon the important terms, definitions, as well as concepts included in the Waves class 11 chapter! 

What is a Wave? 

A form of disturbance that travels through a material medium as a result of repeated periodic motion of the medium particles about their mean positions without any transportation of matter is called a wave.

Characteristics of Waves

Waves have a set of characteristics that have been elucidated in the Waves class 11 chapter. Its summary has been given a rundown below:

  • Particles of a medium traversed by a wave execute comparatively smaller vibrations about their mean positions but aren’t permanently displaced in the direction of wave propagation. 
  • The successive particles of a medium execute a motion quite similar to its predecessors, either along or perpendicular to the line of travel of the wave. 
  • Only transfer of energy takes place during the motion of waves. 

Different Types of Waves

Majorly, there are 3 different types of Waves, i.e. Mechanical, Matter, and Electromagnetic waves. Though the concept has been clearly explained in the Waves class 11 chapter, here are the definitions of these types:

Mechanical Waves

They are produced and propagated in material medium only and are governed by Newton’s laws of motion. Furthermore, this type of wave is bifurcated into 2 types, Transverse and Longitudinal. As explained in Wave class 11 chapter, here are the key details you need to know about types of Mechanical Waves.  

  • Transverse wave motion- in these waves, medium particles vibrate at right angles to the direction of wave propagation. Waves on surface water, strings, and electromagnetic waves are its examples.
  • Longitudinal wave motion- the wave particles move to and fro about their mean positions along the direction of energy propagation. These are also called pressure waves. An example can be sound waves
Transverse vs Longitudinal Wave

Electromagnetic Waves

Production and propagation of these waves require no material medium, and they can pass through the vacuum or any other material medium. The most prominent examples include:

  • Ultraviolet
  • Microwave
  • X-rays
  • Infrared
  • Gamma Rays

Matter Waves

The third and the most important concept included in the Wave class 11 chapter is on the Matter waves. They are associated with moving material particles like protons, neutrons, electrons etc. 

Waves Class 11 Chapter: Important Terms and Definitions

In the Waves class 11 chapter, there are several other terms that have been used to describe the essential properties of a wave. Understanding them is important to find solutions to numerical as well as theoretical problems. Here are some important terminologies which you must be aware of. 


Wavelength (ʎ) is the distance travelled by a disturbance during the period of one vibration of a particle of the medium. For a transverse wave, the wavelength can also be defined as the distance between two crests or two troughs. In contrast, for a longitudinal wave, the wavelength will be equal to the distance from the centre of one compression (or refraction) to another compression.

Wave Velocity

Wave velocity is the rate of time of propagation of a wave in a medium. It is different from the particle velocity, and it depends on the nature of the wave. The formula for wave velocity is:

Wave Velocity (υ) = Frequency (v) x Wavelength (λ)

Amplitude of a wave is the maximum displacement of the constituent medium particles from their mean positions. 

Wave Class 11 Notes

Frequency is the number of vibrations made by a wave-particle in one second. In mathematical equations, it is represented by ‘v’. The S.I. unit for frequency is Hertz (Hz), and the formula is:

 v =1/T
Time Period

The time period refers to the time taken by a medium particle to complete one vibration. Its unit is seconds (s). The formula to calculate time period is:

T = 1/v

Waves Class 11 Important Formulas

Now that you are through with the basic concepts, let us take a quick look at some of the most important formulas included in Wave class 11 chapter.  

The velocity of the transverse wave in a stretched string 
Waves Class 11- Formula of Velocity

Here ‘T’ is the tension in the string, and µ refers to the mass per unit length of the string. µ is also used to refer to the linear mass density of a string. he S.I. unit of µ is kg/m or kg m˄-1. 

The velocity of a longitudinal wave in an elastic medium
Waves Class 11: Velocity of a longitudinal wave in an elastic medium

Here ‘E’ is the modulus of elasticity of the medium, and ρ refers to the density of the medium. In the case of solids, E stands for Young’s modulus of elasticity (Y). 

Source: AtomicSchool

Waves Class 11 Notes for NEET & IIT JEE

Waves Class 11 chapter is also needed to prepare for the physics section in the syllabus for NEET and IIT JEE. Here are the important topics you need to study for NEET and IIT JEE:

What is a Wave?

A wave can be simply described as disturbance that results in the propagation of energy from one place to another without the transport of matter.

What are the two properties for the propagation of a wave in a medium?

1. Elasticity
2. Inertia

What are the types of waves?

1. Mechanical Waves
2. Electromagnetic Waves
3. Matter Waves

What are the various terms related to waves?

1. Amplitude (A): The maximum displacement of the constituent medium particles from their mean positions.
2. Periodic Time (T): The time taken by a medium particle to complete one vibration. Its unit is seconds (s).
3. Wave Frequency (n): The number of vibrations made by a wave-particle in one second.
4. Wavelength (ʎ): The distance travelled by a disturbance during the period of one vibration of a particle of the medium.

Right from class 11, be it the BiPC subjects or MPC subjects, the syllabus is so comprehensive and extensive that the foundation has to be a model of perfection. Apart from the Waves class 11, you also need to clear your concepts of other important chapters of the subject! Exploring education options abroad? Not sure where to study after 12th? Then take the assistance of the counsellors at Leverage Edu who will provide guidance not only in course selection but will also assist in completing the application formalities.

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