Characteristics of EM
waves
1. Electromagnetic waves are transverse in nature.
They are produced by varying electric and magnetic fields. In an
electromagnetic wave, the electric and magnetic fields oscillate perpendicular
to each other as well as perpendicular to the direction of propagation of the
wave. Both electric and magnetic fields vary in phase with each other.
For an electromagnetic wave travelling in positive x direction.
2. In 1865 Clerk Maxwell postulated the existence of
a new current called displacement current which is due to varying electric
field with time. This current exists even in vaccum.
3. Speed of electromagnetic waves in free space
In a material medium, the speed is
4. Average energy densities of electric and magnetic
fields of an electromagnetic wave
Total average energy density is
5. Intensity of an electromagnetic wave in a medium
In vaccum .
Maxwell equations
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