An infinite plane sheet of charge density ${{10}^{-8}}$ C/ ${{m}^{2}}$ is held in air. In this situation, how far apart are two equipotential surfaces whose potential difference is 5 V?

Surface charge density, σ = {{10}^{-8}} C/ {{m}^{2}} Potential difference of two equipotential surface, dV = 5 V

Let the separation between two equipotential surfaces be dr. The E due to infinite plane sheet is given by