Q.How are electromagnetic waves produced? How are the magnitudes of the electric and magnetic fields related to velocity of the electromagnetic wave? OR Draw a diagram showing the propagation of an electromagnetic wave along the X-direction, indicating clearly the directions of the oscillating electric and magnetic fields associated with it.

An oscillating charge creates time-varying E and B fields that sustain each other via Maxwell's equations and radiate outward as an electromagnetic wave, with $E_0 = cB_0$.

Production: A charge at rest produces only a static electric field, and a charge in uniform motion produces a steady magnetic field in addition, but neither radiates energy. Only an accelerating (oscillating) charge produces electromagnetic waves. As the charge oscillates, it produces a time-varying electric field. By Maxwell's modification of Ampere's law, a changing electric field itself produces a (time varying) magnetic field, and by Faraday's law a changing magnetic field in turn produces a changing electric field. These two mutually regenerating, oscillating fields, perpendicular to each other, propagate through space as a transverse electromagnetic wave, without needing a material medium.

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