Electrostatic potential energy in a circuit with and without a battery

[utdiscant]

I have two plate capacitors serially connected in a circuit with a battey and a switch between the battery and one of the plate capacitors.

I have two situaions:

a) I charge the capacitors, cut the switch, and double the internal distance in one of the capacitors.
b) I charge the capacitors, keep the switch and double the internal distance in one of the capacitors.

What is the change of electrostatic potential energy in the two situations?

(This is not the actual exercise I have to solve, just a part of what I need to figure out before going on.)

 

[Redbelly98]

Welcome to Physics Forums.

You'll need to use an equation for the energy in a capacitor ... then think about how it would apply in each case. Please look in your textbook or lecture notes for the equation**, and post back with your thoughts.

**Actually, there are 3 equations for capacitor energy. So part of doing this problem is figuring out which equation best applies in each situation.