Electromagnetic Wave

Chapter-8|Electromagnetic Waves|NCERT 12th Physics:

Electromagnetic Waves:

Electromagnetic waves are the waves which are produced due to change in electric field E and magnetic field B Sinusoidally and propagating through space such that the two fields are perpendicular to each other and perpendicular to the direction of wave propagation.

Source of Electromagnetic Waves:

An oscillating charge produces an oscillating electric field in a space, which produces an oscillating magnetic field, which in turns produces an oscillating electric fields and so on. The oscillating electric and magnetic field regenerate each other as the wave propagates through the space.

The energy associated with the propagating wave comes at the expense of the energy of the source of the accelerated charge.

Electromagnetic waves are also produced when fast moving electron are suddenly stoped by metal target of high atomic number. These electromagnetic waves are called X rays.

Transverse Nature of Electromagnetic Waves:

Since, the oscillation of electric field and magnetic field occur perpendicular to the direction of wave propagation, so electromagnetic wave is a transverse wave.


Equation of Electromagnetic Wave:

Electromagnetic wave form due to oscillation of electric field and magnetic field. So we can write equation of of E and B.

Speed of Electromagnetic Wave:

Maxwell’s also observed that the ratio of peak value of E(E₀) and B(B₀) is equal to speed of light.

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