Properties of Electromagnetic Waves

Electromagnetic waves are composed of oscillating electric and magnetic fields at right angles to each other and both are perpendicular to the direction of propagation of the wave. Electromagnetic waves differ in wavelength (or frequency).

In an electro-negative wave the electric fieldE(vector) and the Magnetic fieldB(vector) oscillate perpendicular to each other and both are perpendicular to direction of propagation of wave.

The source that produce them and methods of their detection are different, but they have the following common properties :

Electromagnetic waves are propagated by oscillating electric and magneticfieldsoscillating at right angles to each other.

Electromagnetic waves travel with a constant velocity of3 x 108ms-1in vacuum.

Electromagnetic waves arenot deflectedby electric or magnetic field.

Electromagnetic waves can showinterferenceordiffraction.

Electromagnetic waves aretransverse waves.

Electromagnetic waves may bepolarized.

Electromagnetic waves needno mediumof propagation. The energy from thesunis received by the earth through electromagnetic waves.

Thewavelength(λ) and thefrequency(v) of electromagnetic wave is related as

c =vλ = ω/k

The S.I. unit of frequency isHertz.

1 Hertz = 1 c / s

The S.I. unit of wavelength is metre.

We however, often express wavelength inAngstromunit [ Å ]

1 Å = 10-10m

Also, 1 nanometer =l nm = 10-9m