Question

Two infinite sheet carry equal and opposite uniform charge of densities $\pm \sigma$. The electric field in the free space between the two sheets will be :

• A. $\frac{\sigma }{{ϵ}_0}$
• B. $\frac{\sigma }{2{ϵ}_0}$
• C. $\frac{2\sigma }{{ϵ}_0}$
• D. Zero

Answer 1

The correct option is A $\frac{\sigma }{{ϵ}_0}$

Electric field at any point near single infinite charge carrying sheet is $\sigma /2{ϵ}_0$. Direction is away from the sheet, if $\sigma$ is positive and towards the sheet, if it is negative.

So due to two infinite sheets of charge, total electric field at any point between the sheets is,

$\frac{\sigma }{2{ϵ}_0}-\frac{-\sigma }{2{ϵ}_0}=\frac{\sigma }{{ϵ}_0}$