A parallel-plate capacitor has capacitance 6.50 F.

(a) How much energy is stored in the capacitor if it is connected to a 20.00-V battery? in J (b) If the battery is disconnected and the distance between the charged plates doubled, what is the energy stored? in J (c) The battery is subsequently reattached to the capacitor, but the plate separation remains as in part (b). How much energy is stored? in J