Suppose that at t=0 a charge of 1 microC is deposited at one
point of a copper sphere whose diameter is one meter. I used
to say that "the equilibrium is going to be established very
quickly, perhaps in a couple of nanoseconds or so. Why?
Because it can not be faster than 3.3 ns; the time light
needs to cover the distance of 1 m in air.
1) Do charges travel to final destinations through the entire
volume or do they travel mostly near the surface?
2) How to calculate the time needed to establish equilibrium?
I suspect it is much longer than ~3 ns but I do not know how
to estimate it realistically.
Ludwik Kowalski