(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 introduced 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.

Explanation

To solve the problem step by step, we will break it down into parts (a) and (b) as given in the question.

### Part (a)

1. **Understanding the System**:
- We have a large spherical conducting shell with a charge +Q on its surface and a small conducting sphere with charge +q placed at its center.
- The radius of the large shell is R, and the radius of the small sphere is r.

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