A friend asked me this question: There is a capacitor with capacitance C, charge Q on either plate and an electric field E between the plates. The energy stored in the capacitor is then given by (C.V^2)/2, where V is E.(distance between plates). Now, take another similar capacitor, and connect it across the original capacitor like shown. ----||---- ---------| |-------- ----||---- Then, due to redistribution of the chrges, the electric field between plates of each capacitor becomes E/2. The equivalent capacitance is 2C and the total energy stored in the 2 capacitors is now (C.V^2)/4. What happens to the other (C.V^2)/4? I think so much energy is lost during redistribution of charges. But am not sure.. Any help?