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WHAT ARE ELECTROMAGNETIC WAVES?
The term electromagnetic wave describes the way electromagnetic radiation (EMR) moves through space. Different forms of EMR are distinguished by their wavelengths, which vary from many yards (meters) to a distance smaller than the diameter of an atomic nucleus. The full range, in decreasing order of wavelength, goes from radio waves through microwaves, visible light, ultraviolet and X-rays to gamma rays and is known as the electromagnetic spectrum. Electromagnetic waves have many applications, both in science and in everyday life.

Properties of electromagnetic waves

1. They travel in free space with a speed 3 x 108 m/s
2.The amplitude of the electric and magnetic vectors are related as c = E/B.The E and B fields are perpendicular to each other and to the direction of propogation of the wave.The fields have the same frequency and are in phase.
3.The velocity in a medium depends on the electric and magnetic properties of the medium.
4.The energy of the electromagnetic wave is divided equally between electric and magnetic vectors.
5.Electromagnetic waves transport linear momentum as well.When em waves strikes a surface it exerts a pressure on the surface.If the total energy transferred to a surface in time t is U,the total momentum delivered on the surface is
P = U/c
6.The electric vector is responsible for optical effects and is called "light vector".


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