導電體的特性

The whole of the conductor should be at the same potential.
If it so happened that a charge is inside the conductor, its presence would raise the potential in the interia of the conductor. As a result, the difference in potential between the interia and surface causes the charge to move to the lower potential side, i.e. the conductor surface which is an equipotential surface.

由於d charge可以自由走動, 同極相拒, 到最後穩定(equilibrium) 時, 就會o係導電體既表面...