Two conducting large plates `P_(1) & P_(2)` are placed parallel to each other at very small seperation 'd'. The plate area of either face of plate is A. A charge +2Q is given to plate `P_(1)` & -Q to the plate `P_(2)` (neglect ends effects). If plate `P_(1) & P_(2)` are now connected by conducting wire, then total amount of heat produced is

Options

A. `(4Q^(2)d)/(3in_(0) A)`
B. `(9Q^(2)d)/(8in_(0) A)`
C. `(3Q^(2) d)/(8 in_(0) A)`
D. None of these

Answer

B

Explanation

`C=(varepsilon_(0)A)/d U_(i)=(1.5Q)^(2)/(2c)=(2.25Q^(2)d)/(2C)`
`Rightarrow U_(i) = (9Q^(2)d)/(8varepsilon_(0)A)`
After connecting
Heat `=U_(i)-U_(f)=(9Q^(2))/(dvarepsilon_(0)A)`