Two infinitely long parallel conducting plates having surface charge densities $+\mathrm{\sigma } \mathrm{and} -\mathrm{\sigma }$, respectively, are separated by a small distance. The medium between the plates is vacuum. If £o is the dielectric permittivity of vacuum, then the electric field in the region between the plates is

Given that conducting plates have surface charge densities $+\mathrm{\sigma } \mathrm{and} -\mathrm{\sigma }$, respectively. Since the sheet is large, the electric field E at any point near the sheet will be perpendicular to the sheet.

If $\mathrm{\sigma }$ is surface charge density then, electric field between the plates

$$\begin{gathered} =\frac{\mathrm{\sigma }}{2{\mathrm{\epsilon }}_0}+\frac{\mathrm{\sigma }}{2{\mathrm{\epsilon }}_0} \\ =\frac{\mathrm{\sigma }}{{\mathrm{\epsilon }}_0} \mathrm{volt}/\mathrm{metre} \end{gathered}$$