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Introduction of Waves

Waves refer to the transfer or flow of energy from one point to another without the transfer of matter. It appears in the form of oscillations when they pass through any medium (in case of water waves or sound waves) or without any medium (in case of electromagnetic waves). They are present around us in both visible and invisible forms. Some of the types of waves are radio waves, sound waves etc. 

An individual is completely dependent on a wide range of waves for wireless communications. When you call your friend then the entire communication on the phone happens through the transmission of waves. The communication from the sender to the receiver appears in the form of a waveform. Your phone converts the received voice signal into an electrical signal. Later, these electric signal travels either wirelessly or via copper wires to the receiver through an antennae. In this way, waves help in communication between people. 


Types of Waves:


Waves occur in various forms. There are three types of Waves


  • Mechanical Waves

    1. Transverse waves

    2. Longitudinal waves

  • Electromagnetic waves

  • Matter Waves


1) Mechanical waves


The mechanical waves are seen as a propagation of a specific disturbance that travels in a material medium. This type of wave is a result of the oscillation of matter. In this case, the transfer of energy happens through a medium.

The oscillating material performs motion at a stationary point. There is little translational motion involved in this type of propagation. The distance covered by the propagation of a wave is determined by the transmission medium. 

This wave is the outcome of the continuous periodic movement of the particles. In this type of wave, the entire disturbance that comprises of momentum and energy is passed from one wave-particle to its immediate next particle in the medium. Mechanical waves do not possess the ability to pass through the vacuum. There is no mass transfer possible during the movement of wave particles.


Some of the examples of a mechanical wave are the “vibration of a string”, tsunami waves, earthquake waves, ultrasounds, waves in slink, oscillations in spring etc.


Mechanical waves are measured by dividing displacement by the wavelength. When the dimensionless factor is below one, it generates harmonic effects. When this factor increases from one, then it becomes the reason for turbulence. It is seen in the form of waves breaking on the beach.


There are two types of Mechanical waves, as Transverse waves and Longitudinal waves 


a) Transverse Waves


In this type of wave, the medium vibrates to and fro at right angles to the direction of propagation of wave/energy. In other words, when the energy particles and the wave particles form a perpendicular angle to each other, then it is called a transverse wave. One of the best examples of transverse waves is radio waves, microwaves, ocean waves, wiggling string and polarized waves.


b) Longitudinal Wave:

This is another important variation of a wave. Here, the wave particles vibrate to and fro in the direction of the propagation of wave/ energy. There is a zero-degree angle formed between the wave particles and the energy particles. It can also be put as the displacement of the medium occurs in the direction of the movement of the wave. Some of the examples of this type of longitudinal wave are sound waves, and pressure wave.



2) Electromagnetic Waves


In electromagnetic waves, there is no need for the presence of any medium for the propagation of the wave. In other words, electromagnetic waves travel from one place to another in a vacuum and at the same speed. As in these waves, periodic changes take place in the magnetic fields; they are called as electromagnetic waves.

Electromagnetic waves are formed by the combination of magnetic and electric fields. The light and the colour that you see are due to the presence of electromagnetic waves. Some of the important examples of electromagnetic waves are: Microwaves, Lightwaves, thermal radiation, X-rays, Radio waves and Ultraviolet waves


Properties of Electromagnetic Waves:


There are some important attributes of electromagnetic waves as mentioned below:


These waves travel with the speed of light.


They can be polarized.


They show a transverse nature.


They carry momentum



3) Matter Waves 


These waves are also referred to as De Broglie waves. According to Louis de Broglie’s theory, a beam that comprises of electrons can get deflected like any other ray of water wave or electromagnetic radiation.

These types of waves show properties similar to the properties of a matter, such as atoms, etc. There are various equations represented as De Broglie's equation that signifies the “dual” nature of matter. The frequency of matter waves is directly dependent on the kinetic energy.


Properties of Waves


A wave is characterized by different properties of it. These properties are amplitude, frequency, wavelength, velocity and period. To get more clarity on these elements, let us understand each of them one by one. 




The amplitude of a wave is measured in meters. It denotes the energy contained in the wave. The wave that has more amplitude is more powerful and energetic. The amplitude of a wave is the maximum displacement or the total distance travelled by a wave in the medium.




Wavelength is calculated as the distance between two successive troughs or crests of the wave. It is measured in meters. Wavelength of a wave is denoted by lambda and it is equal to the velocity of a wave (in meters/sec) divided by the wave frequency (in Hertz).


Time Period


Time Period is the total time that a wave takes to complete a single cycle. It is measured in seconds. It is represented by the alphabet ‘T’. The inverse of the time period is the frequency of a wave. 




The velocity of any wave is the speed at which a wave travels in one medium. It is measured in meters/seconds. Velocity is calculated as the product of wave frequency and the wavelength, or division of wavelength and the period. 


Wave Speed Formula


Having understood the different types of waves, let us now understand Wave Speed Formula. Wave speed is viewed as the distance that any wave travels at a specified amount of time. It implies the number of meters that a wave travels in every second. 


Wave speed is also related to wave frequency and wavelength. It can be understood by the following equation:


                                         Speed = Frequency  x  Wavelength


When you know the values of the frequency and the wavelength, you can easily calculate wave speed with this formula.