Q: How the electromagnetic waves are produced?
Ans: We know that a charge at rest produces an electric field around it but no magnetic field where a moving charge produces both electric and magnetic fields but if the charge is moving with constant velocity there will be no charge in the values of the electric and magnetic fields,So all electromagnetic waves are produced.Now if charge is moving with non zero acceleration, both the electric and magnetic field will change, there by producing the em waves. So we conclude that an accelerated charge emits electromagnetic waves.
Important features or characteristics or facts about electromagnetic waves:
(i) em waves are produced by accelerated or oscillating charges.
(ii) They don’t require any material medium for their propagation.
(iii) They travel in free space with a speed of light.
(iv) A sinusoidal variation occurs in both the electric and magnetic field vectors.
(v) em waves are transverse in nature.
(vi) Velocity of em waves depends on electric and magnetic properties of medium through which travel and independent of amplitude of field vectors.
(vii) Velocity of em waves in a dielectric is less than velocity of light.
(viii) em waves carry energy which is distributed equally between electric and magnetic fields.
(ix) The electric vector is responsible for the optical effects of an em waves so it is known as the light vector.
(x) em waves are uncharged so they are not deflected by electric and magnetic fields.
These are the features of electromagnetic waves.