10C of charges are placed on a spherical conducting shell. A particle with a charge of –3C is placed at the center of the cavity. The net charge on the inner surface of the shell is:
10C of charges are placed on a spherical conducting shell. A particle with a charge of –3C is placed at the center of the cavity. The net charge on the inner surface of the shell is:
Explanation
In a conductor, the electric field inside the conductor (in the material itself) must be zero. So:
The inner surface of the shell must carry a charge that exactly cancels the field from the charge inside the cavity.
Since there's a –3 C charge at the center, the inner surface must have a charge of +3C to neutralize the field inside the conductor.