Question

Two thin infinite parallel sheets have uniform surface densities of charge +σ and –σ. Electric field in the space between the two sheets is(a) $\frac{\sigma}{\epsilon_{0}}$(b) $\frac{\sigma}{2\epsilon_{0}}$(c) $\frac{2\sigma}{\epsilon_{0}}$(d) zero

Answer 1

answer : option (a)$\frac{\sigma}{\epsilon_{0}}$

explanation : we know, electric field intensity due to infinite large sheet of uniform surface charge density $\sigma$ is given by, $E=\frac{\sigma}{2\epsilon_0}$

so, electric field intensity due to sheet of surface charge density $+\sigma$ is $E_1=\frac{\sigma}{2\epsilon_0}$ away from the sheet

and electric field intensity due to infinite sheet of surface charge density $-\sigma$ is $E_2=\frac{\sigma}{2\epsilon_0}$ towards the sheet.

here have you noticed direction of electric field of $E_1$ and $E_2$ are in same direction.

so, net electric field , E = $\frac{\sigma}{2\epsilon_0}+\frac{\sigma}{2\epsilon_0}$

= $\bf{\frac{\sigma}{\epsilon_0}}$