**1. The problem statement, all variables and given/known data**

A spherical capacitor comprises two thin metal spheres of different radii but with

a common centre. The following series of operations is completed: The spheres are mutually connected by an internal wire. The outer sphere is raised to potential +V with respect to ground. The internal connection is broken. The outer sphere is returned to ground potential. Determine the final potential and the final charge on the inner sphere.

**2. Relevant equations**

Gauss' Law (integral form)

**3. The attempt at a solution**

As the spheres are connected by a wire initially I assume when the outer sphere is raised to V the inner sphere must be too. As they are at the same potential I think the charge on the inner sphere must be 0 at this point so that there is no field between the spheres (Gauss). When the connection is broken the inner sphere must then retain 0 net charge, and so when the outer sphere is returned to ground potential i think the inner sphere must have no charge and be at 0V with respect to ground.

This is the best argument I could come up with but I'm struggling to convince myself! Any help/confirmation of this answer would be appreciated