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Electromagnetic Waves The waves are defined as the disturbance through any medium of substance. The electromagnetic

waves are the waves which are generated bycoupling of magnetic field with electric field. These

waves are in perpendicular direction to both the electric and magnetic and also perpendicular to each

other. These are first studied by James Clerk Maxwell  and Heinrich Hertz . Maxwell  discovered that

changing electric field induced magnetic field and also vice-versa. These waves are existed due to

change in these fields. These are continued till it is not absorbed by matter.

The German physicist Hertz  used the theory of Maxwell for the radio waves and gives the unit of

frequency. He showed all the properties of the electromagnetic waves as these waves do not required

any medium for their movement. Here we are discussing all about these waves, transmission, their

generation process, and their properties.

What are Electromagnetic Waves?Back to Top

Let us consider an Electromagnetic field. When there is a periodic disturbance in the electric and

magnetic fields, we are able to see this Electromagnetic wave. These waves have a frequency that

comes in the range of electromagnetic spectrum.

 An Electromagnetic spectrum is the spectrum containing all possible range of frequencies coming in

the electromagnetic wave. These waves do not need the medium for their Propagation. These waves

can be polarized and are transverse in nature. Medium is not required for their propagation.

Example: Radio waves, Light waves, thermal radiation, X ray etc.

Electromagnetic Waves DefinitionBack to Top

These waves were discovered by famous physicist James Maxwell . They can be defined as "When

electric and magnetic fields fluctuate together they lead to formation of the propagating waves

called Electromagnetic waves." 

Properties of Electromagnetic Waves

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Back to Top

Electromagnetic radiations are basically streams of photons. It is a transverse wave. In a transverse

wave the medium has particles that vibrate in a direction perpendicular to the direction of the

propagation of wave.

The various properties of Electromagnetic waves are: 

1. The Velocity of electromagnetic wave in vacuum is 3 × 108 m / s.

2. The existence of medium is not essential for propagation.

3. In vacuum, E.M waves travel with light velocity.

4. E.M waves can be polarized.

5. E.M waves are transverse in nature.

6. E.M waves have momentum.7. There is no deflection on account of magnetic or electric field.

8. They can exhibit diffraction and interference.

Examples of Electromagnetic WavesBack to Top

Radio waves, Light waves, thermal radiation, X ray, visible light, microwave, infrared, gamma rays etc.

are the example of electromagnetic waves. These waves together form the electromagnetic spectrum. 

Speed of Electromagnetic WavesBack to Top

Electromagnetic waves can have a wave or particle nature. When wave it is characterized

by frequency and wavelength.In vacuum the waves travel with a speed of light = 3 × 108 m/s. If a

medium is considered then it would depend upon the refractive index of the medium.

Electromagnetic SpectrumBack to Top

The Electromagnetic spectrum consists of all the possible frequencies of electromagnetic radiations.

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The electromagnetic spectrum starts from radio waves and goes beyond the gamma rays. It is very

vast range of frequencies.

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Electromagnetic Spectrum WavesBack to Top

EM spectrum consists of different types of waves with different wavelength and frequencies. The

wavelength and the frequency of the wave are inversely proportional to each other. The following are

the types of Electromagnetic Waves in the spectrum:

1. Radio Waves 

2. Micro Waves 

3. Infrared Rays 

4. Visible Light 

5. Ultraviolet 

6. X rays 

7. Gamma Rays 

Types of RadiationBack to Top

There are seven types of electromagnetic waves which can be classified as follows:

Radio Waves : 

1. These are the waves that are emitted by radio stations, during transmission or by TV stations

etc. they are also emitted by stars.

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2. They Can range from few millimeters to large wavelength.

3. They are used by antennas.

4. They are used for data transmission via modulation.

Micro Waves : 

1. The waves emitted by the microwave oven, yes they are the microwaves!

2. They are used by astronomers to study the structures of galaxies.

3. They are of two types Super high frequency and extremely high frequency.

4. They are used by Wi-fi.

Infrared Rays : 

They are emitted by everything that is warm and hot.

They are of three types viz.

1. Far infrared rays

2. Mid infrared rays

3. Near infrared rays.

Visible Light : 

1. These are emitted by everything from a bulb to particle striking other particles. These waves

are detected by human eye.

2. The wavelength lies between 380 nm to 760 nm3. They are used in optical fiber communication medium.

Ultraviolet : 

1. They are emitted by sun, is harmful for human body. They cause skin burn.

2. They can ionize atoms.

3. They can cause skin cancer.

4. They cause mutagen

5. They are absorbed by ozone layer mostly.

X rays : 

1. They are used by doctors.

2. They can interact with matter.

3. They cause Compton Effect.

They are of two types viz.

  Hard ray

  Soft X-ray.

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4. VHF.

  Much exposure can cause cancer.

  They are used by antennas.

  They are used for data transmission via modulation.

  These are the waves that are emitted by radio stations, during transmission or by TV stations

etc. they are also emitted by stars.

  They can range from few millimeters to large wavelength.

  They are used in Phones, TV, radio etc.

Is Sound an Electromagnetic Wave?Back to Top

The radio waves are used to carry the sound waves to the larger distance. It is composed of long

radio waves, AM and FM waves. So, from this a question “Is Sound an Electromagnetic Wave”

could be positively answered. Yes the sound is electromagnetic waves. In fact, we can say that any

radiation of whatsoever the wavelength it is the part of the EM spectrum.

Energy in Electromagnetic WavesBack to Top

The Energy in electromagnetic waves are half due to electric field and half due to magnetic field.

Electromagnetic radiation is the transfer of energy by electromagnetic waves. Basically it is the

movement of waves from one place to another.For example: X rays and Gamma Rays.

Electromagnetic FieldBack to Top

Electromagnetic fields are produced by electromagnetic waves. Basically they are produced by every

charge particle that is moving. Now as the waves have a particle as well as the wave nature so this

field is also produced by electromagnetic waves. It is produced in the area surrounding the wave. It is

the fundamental force of nature. Basically the field is produced by electric and magnetic field, by static

as well as moving charges. It is described by Maxwell equations.Radio WavesBack to Top

The Radio waves are the very starting point of the EM spectrum. They have wavelength in the range

of 1 millimeter to several kilometers. The Radio wave frequency lies between as low as 3 Hz to as

high as 300 GHz. The radio waves are generally used in communication systems.

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Infrared Rays

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The infrared waves are of wavelength well below the visible region of the EM spectrum. The infrared

are not visible to our eye since they are outside the narrow window of the visible frequencies. In other

words, we can say that we are blind for all the spectrum except the visible spectrum.

The heat emitted by the body after the flame extinguishes is an examples of the infrared waves.

Ultraviolet RaysBack to Top

In the Electromagnetic spectrum the rays having frequencies higher than the violet color of the visible

light and frequency lower than the x rays is termed as the ultraviolet rays. 

In terms of wavelength we can define the ultraviolet rays as the rays having wavelength less than the

violet visible light and greater than the x rays.Ultraviolet rays wavelength varies from 10 nanometer  to

the 400 nanometer. 

Ultraviolet spectrum of the electromagnetic spectrum is basically divided into three parts.

1. Near ultraviolet region

2. Far ultraviolet region

3. Extreme ultraviolet region.

It show three regions are made on the basis of the increasing energy.

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Gamma RaysBack to Top

The gamma rays are discovered by a French chemist and physicist, Paul Ulrich Villard , in 1900.

1. The gamma rays are the high frequency, high energy and shorter wavelength rays.

2. They lie above the X – rays in the electromagnetic spectrum and are distinguishable from the

X – rays by the source of their origins.

They have too many application in medical sciences and nuclear physics. 

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 X Rays

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Wilhelm Roentgen named the rays he discovered as X – rays. The X – rays belongs to the

electromagnetic spectrum. The X – rays extends from the ultraviolet band to gamma rays band.

 Although their is very thin line between the X-ray and gamma rays but they are distinguished by the

source of their generation. They have their own applications in medical science in diagnosis.

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