Question

The energy of a charged capacitor resides in
(A) The electric field only
(B) The magnetic field only
(C) Both electric and magnetic field
(D) Neither in electric nor in magnetic field

Answer 1

Hint : In the limit of a fully charged capacitor, there is no displacement current maintaining a magnetic field and all the energy is stored in the electric field.

Complete Step By Step Answer:
When a capacitor is charging, the rate of change of the electric field between the plates is not-zero, and from the Maxwell-Ampere equation this causes a circulating magnetic field. Magnetic field will be present due to the change in the electric field.
However, when the capacitor is charging, the magnetic field does not remain the same or will not be static. This results in EM (electromagnetic) waves which radiate energy. The energy put into the magnetic field during charging is lost as it cannot be fed back to the circuit by the capacitor.
For a constant potential on the capacitor, there is no magnetic field and that is the case usually considered for calculation and the same has been asked here in question.
From the given multiple choices – the option A which says “the electric field only” is the correct answer.

Note :
While charging a capacitor, the current will generate a Magnetic field and there will be some energy stored in it. But when charging stops, the Magnetic field will "collapse" and so, it should not be considered in energy calculations when charged.