Charge distribution over two thin concentric spherical shells

[captainjack2000]

Homework Statement

"A thin conducting spherical shell of radius a carries a charge q. Concentric with this is another spherical shell of radius b>a carrying a net charge Q. Describe how the charge is distributed between the inner and outer surfaces of the shells. What is te capacitance of the two shells?"

Homework Equations

The Attempt at a Solution

Is it correct to say that there would be a charge +q on the outer surface of the inner shell. Due to induced charge there would then be a charge -q on the inner surface of the outer shell. Therefore there would be a charge +Q-q on the outer surface of the outer shell.

For the capacitance does it want the capacitance of the overall system. C=Q/V ??

 

[latentcorpse]

Q is the net charge, when i did this question i took it to mean that Q=-q as it is induced by the +q on the inner sphere. note: to be a capacitor the two plates have to carry equal and opposite charges.

use gauss' law to get the field and then go from there in order to get the capacitance.

 

[granpa]

+Q-q ?