The infinite plane $z = 0$ is earthed and the infinite plane $z=d$ carries a charge of $\sigma$ per unit area. Find the electrostatic potential between the planes.
I have tried to compute the electric field between the two plates;the field points vertically downwards between the plates and has magnitude $\frac{\sigma}{ε_0}$, by Gauss' law. But above the plates, the field points vertically upwards with equal magnutide.
By symmetry should the magnitude of the total field be $\frac{\sigma}{2ε_0}$ and hence is the potential $\frac{\sigma}{2ε_0}\times z$ ? Or do I only take into account the component vertically downwards?
