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. `(23CV^(2))/(6)`
C. `(3CV^(2))/(2)`
D. `(9CV^(2))/(2)`

Answer

C

Explanation

Total charge `= (2C)(2V) + (C ) (-V) = 3CV`
`:.` Common potential `= (3CV)/(3C) = V`
`:.` Energy `= (1)/(2)(3C)(V)^(2) = (3)/(2)CV^(2)`