Question

(a) A charge +Q is placed on a large spherical conducting shell of radius R. Another small conducting sphere of radius r carrying charge ‘q’ is introdcued inside the large shell and is placed at its centre. Find the potential difference between two points, one lying on the sphere and the other on the shell. 

(b) How would the charge between the two flow if they are connected by a conducting wire? Name the device which works on this fact.

Answer 1

(a) For external points, the charge may be supposed to be concentrated at the centre, so

For internal points, the potential is same as on the surface

(b) When both shells are connected by a conducting wire, whole charge of inner shell will flow to outer shell.

Device Working on this principle is Van de Graaff Generator.