Electromagnetic waves can be produced by . . . . . . .

$A$ charged particle oscillates about its mean equilibrium position with a frequency of $8 \times 10^9 \text{ Hz}$. What is the frequency of the electromagnetic waves produced by the oscillator?

The charge on a parallel plate capacitor varies as $q = q_0 \cos(2\pi \nu t)$. The plates are very large and close together (area $= A$,separation $= d$). Neglecting the edge effects,find the displacement current through the capacitor.

The Maxwell-modified form of Ampere's circuital law is .......

The source of a time-varying magnetic field may be:
$(A)$ A permanent magnet
$(B)$ An electric field changing linearly with time
$(C)$ Direct current
$(D)$ A decelerating charged particle
$(E)$ An antenna fed with a digital signal
Choose the correct answer from the options given below:

In the charging of a capacitor,what is the contradiction in Ampere's circuital law?