Question

Three large identical conducting plates of area A are closely placed parallel to each other as shown (the area A is perpendicular to plane of diagram). The net charge on left, middle and right plates are $Q_L,Q_M$ and $Q_R$ respectively. Three infinitely large parallel surfaces $S_L,S_M$ and $S_R$ are drawn passing through middle of each plate such that surfaces are perpendicular to plane of diagram as shown. Then pick up the correct option(s).

• A. The net charge on left side of surface $S_L$ is equal to net charge on right side of surface $S_R$
• B. The net charge on left side of surface $S_L$ is equal to net charge on right side of surface $S_M$.
• C. The net charge on left side of surface $S_L$ is equal to net charge on right side of surface $S_L$
• D. The net charge on right side of surface $S_L$ is equal to net charge on left side of surface $S_R$

Answer 1

Answer: (A), (B), (C), (D)

The net charge on right side of surface $S_L$ is equal to net charge on left side of surface $S_R$



Since, electric field on plate at surface $S_L$ is zero, net charge on left side of $S_L$ is equal to net charge on right side of $S_L$. Further net charge between any two dotted surfaces (out of $S_L$ $S_M$ and $S_R$ ) is zero from Gauss theorem.

$\therefore$ Charge on left most surface $q_1$ is equal to charge on right most surface $q_6$, (i.e $q_1=q_6$). Hence, all statements are true.