A spherical metal body has +Q charge, uniformly distributed over its outer surface. The body has a cavity at its centre. Select proper procedure from those given below which will change the charge on the outer surface of this body from +Q to –Q. |
Charge –2Q is inserted in the cavity and is kept insulated from the inner surface of the cavity Charge –2Q is brought closer to the body externally and kept at some small distance away from it Another metal sphere having total charge –2Q distributed on its surface is kept in contact with the given spherical body for some time and then the two are separated A metal body having charge –Q is inserted in the cavity and kept touching the inner surface of the cavity |
Charge –2Q is inserted in the cavity and is kept insulated from the inner surface of the cavity |
The correct answer is Option (1) → Charge –2Q is inserted in the cavity and is kept insulated from the inner surface of the cavity Now to change net charge on outer surface of sphere as –Q. Place a charge –2Q at centre of sphere without making a contact with sphere. |