College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 34

A parallel-plate capacitor has capacitance 3.00 F. (a) How much energy is stored in the capacitor if it is connected to a 6.00-V battery (b) If the battery is disconnected and the distance between the charged plates doubled, what is the energy stored (c) The battery is subsequently reattached to the capacitor, but the plate separation remains as in part (b). How much energy is stored (Answer each part in microjoules.)