# Homework Help: Electromotive Force problem dealing with spherical shells

1. Jan 16, 2009

### pentazoid

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

To concentric metal spherical shells , of radius a and b , respectively , are separated by weakly conducting material of conducting sigma

a) If they are maintained at a potential difference V, what current flows from one to the other?

2. Relevant equations
V=-$$\int$$E *dl
V=IR

3. The attempt at a solution

E(from a to b)=Q/(4$$\pi$$$$\epsilon$$r^2)==> V(from a to b)= Q/(4$$\pi$$$$\epsilon$$r

E(from b to infinity)= Q/(4$$\pi$$$$\epsilon$$0r^2)==> V(from b to infinity)= Q/(4$$\pi$$$$\epsilon$$0r

I=V/R=(Q/((4$$\pi$$$$\epsilon$$R))*(1/b - 1/a) )+(Q/((4$$\pi$$$$\epsilon$$0R)*(1/b-1/a)