`A, B, C, D, E,` and `F` are conducting plates each of area `A`, and any two consecutive plates are separated by a distance `d`, The energy in system after the switch `S` is closed is`
.

Options

A. `(3epsilon_(0)A)/(2d)V^(2)`
B. `(5epsilon_(0)A)/(12d)V^(2)`
C. `(epsilon_(0)A)/(2d)V^(2)`
D. `(epsilon_(0)A)/(d)V^(2)`

Answer

C

Explanation

`C_("eff") = (epsilon_(0)A)/(d)` since effective capacitance between plates A and E is zero
`:. U = (1)/(2) CV^(2) = (epsilon_(0)A)/(2d) V^(2)`