A parallel-plate capacitor has plates of area A and separation d and is charged to a potential difference V. The charging battery is then disconnected, and the plates are pulled apart until their separation is 2d. Derive expressions for the following quantities: (Use only variables or symbols stated above along with the following as necessary: ?0.)
a) New potential difference
b) The inital stored energy
c) The final stored energy
d) the work required to seperate the plates