Question

Two thin infinite parallel sheets have uniform surface densities of charge $+\sigma$ and $-\sigma$. Electric field in the space between the two sheets is:

• A. $\sigma /{ϵ}_0$
• B. $\sigma /2{ϵ}_0$
• C. $2\sigma /{ϵ}_0$
• D. zero

Answer 1

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

Electric field due to positive charged plate $E^{\prime }=\frac{\sigma }{{2ϵ}_0}$
Similarly for negative charged plate $E^{\prime \prime }=\frac{\sigma }{{2ϵ}_0}$
$\therefore$ total electric field between the fixed plates $=\frac{\sigma }{2{ϵ}_0}+\frac{\sigma }{2{ϵ}_0}$ $=\frac{\sigma }{{ϵ}_0}$