Three metallic plates out of which the middle is given charge Q as shown in the figure. The outer plates can be earthed with the help of switches `S_1 and S_2` . The area of each plates is the same. Answer the following question based on the given passage.

The charge that will flow to the earth through `S_2` when both switches `S_1 and S_2` are grounded simultaneously is

Options

A. `Q`
B. `-Q`
C. `3Q//4`
D. `Q//4`

Answer

D

Explanation

`((Q-q))/(epsilon_(0)A)3d=(qd)/(epsilon_(0)A)`
or `q=(3Q)/(4)`