Capacitance of three concentric spherical shells?

[anban]

Homework Statement

I do not have a specific question, I am just wondering how one would go about finding the capacitance of three concentric spherical shells. Suppose the outer radius of the each shell is a, b, and c from the center outwards.

Homework Equations

E= -gradV
C = Q/ V, which for two shells = (4∏ε)/ ((1/a)-(1/b)) ... this is the voltage between the two shells.

The Attempt at a Solution

If we found the voltage between the two inner shells and then the to outer shells, perhaps we could add them? What do you you all think?

 

[ehild]

You can add the voltages across series elements.

ehild