Question

Where do charges reside in the case of a charged conductor?
A) Inside the conductor
B) On the outer surface of the conductor
C) On the inner surface of the conductor
D) Anywhere outside the conductor

Answer 1

Hint: Recall whether an electric field exists inside a conductor or not. Coulomb’s law states that free charges must be as far away as possible.

Complete step by step solution:
The electric field inside the conductor is zero. If the field inside the conductor is not zero then the free electrons will move under the effect of that field and there will be flow of current even without applying any potential difference, which is practically impossible.

This happens because when a conductor is given some charge, it distributes itself in a manner that the field inside the conductor becomes zero. In order to establish this situation the charge given is distributed on the outer surface of the conductor such that the surface becomes equipotential which ensures that current even on the surface also becomes zero.

When placed in an external electric field, the electrons tend to migrate to one side of the conductor and an electric field is created inside the conductor itself due to separation of positive and negative charges, as is evident from the pic. In case of conductors, this electric field is always equal to that of the external electric field and hence the external field is neutralized. Hence all the charges move as far away as possible, i.e. on the surface of the conductor.

Therefore option (B) is the correct option.

Note: If there is an electric field inside the conductor then charges will move on their own which is not practical. If there is an electric field inside the conductor then an electric force which will accelerate the charges inside which is not observed. The charges reside on the surface in a manner so as the system stays in equilibrium.