How does a charge q oscillating at certain frequency produce electromagnetic waves ?
Sketch a schematic diagram depicting electric and magnetic fields for an electromagnetic wave propagating along the Z-direction.

Explanation

An electric charge at rest has an electric field in the region around it, but no magnetic field. A moving charge, however, produces both electric and magnetic fields. If the charge is moving with constant velocity (that is, the currentis not changing with time), the fields will not change with time and no electromagnetic wave can be produced. If, however, the motion of the charge is accelerated, the electric and the magnetic fields will change with space and time, then it produces electromagnetic waves. Hence we conclude that an accelerated charge emits electromagnetic waves.
In an oscillatory LC circuit, charge oscillates across the capacitor plates. An oscillating charge has a nonzero acceleration, hence it emits electromagnetic waves of frequency same as that of the oscillating charge.

Fig. shows the graphical representation of an electromagnetic wave in which the electric field vector `vecE` and the magnetic field vector `vecB` are vibrating along Y and X-directions respectively , and the wave is propagating along Z-direction. Both `vecE and vecB` vary with time and space and have the same frequency