A parallel plate capacitor of capacitance C is connected to a battery and is charged to a potential difference V. Another capacitor of capacitance 2C is ismilarly charged to a potential difference 2V. The charging battery is now disconnected and the capacitors are connected in parallel to each other in such a way that the poistive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is

Options

A. zero
B. `(25CV^(2))/(6)`
C. `(3CV^(2))/(2)`
D. `(9CV^(2))/(2)`

Answer

C

Explanation

Common potential `V'=(2Cxx2V-CV)/(2C+C)=V`
The energy strored in capacitors
`=(1)/(2)(C+2C)V'^(2)=(3CV^(2))/(2)`