Two infinite sheets of uniform charge density $+\sigma$ and $-\sigma$ are parallel to each other as shown in the figure. Electric field at the

Since the charge on sheet-1 is positive and the charge on sheet-2 is negative, net electric field intensity towards left (outside the plates) is ${\mathrm{E}}_{\mathrm{L}}=-\frac{\mathrm{\sigma }}{2{\mathrm{ϵ}}_0}+\frac{\mathrm{\sigma }}{2{\mathrm{ϵ}}_0}=0$

towards right (outside the plates) is, ${\mathrm{E}}_{\mathrm{R}}=\frac{\mathrm{\sigma }}{2{\mathrm{ϵ}}_0}-\frac{\mathrm{\sigma }}{2{\mathrm{ϵ}}_0}=0$

But at the mid point (between the plates) both are in same direction (towards right), ${\mathrm{E}}_{\mathrm{M}}=\frac{\mathrm{\sigma }}{2{\mathrm{ϵ}}_0}+\frac{\mathrm{\sigma }}{2{\mathrm{ϵ}}_0}=\frac{\mathrm{\sigma }}{{\mathrm{ϵ}}_0}$