Question

Why does excess charge lie on the surface of a conductor?

Answer 1

Hey.

Here is the answer.

The electrons in the lattice of a conductor is relatively free from that of insulators . But as the surface of a conductor is exposed so there is difference between attractive forces on the electrons inside the lattice and on the surface.
The electrons on the surface are free to move and hence are more better carrier of charge .

Also, One way to think about it is that prior to the placement of excess charge on the object, it is electrically neutral. So you can almost pretend that there is nothing inside the object at all. No atoms, no protons, no neutrons, no electrons, no nothing. Pretend that object is the full extent of our universe and its boundaries are the boundaries of our existence. If you now place all these excess charges inside this empty space, they will move as far away from each other as possible. Ergo, they will move to the surface.

So, excess charge lie on the surface of a conductor.

Thanks.