Question

Using guass' law, find the electric field of a flat, thin,infinite nonconducting sheet with uniform positive surface charge density σ. Now bring this sheet near another identical shet with opposite surface charge density. Find the field between the two plates. Draw any relevant diagrams

Answer 1

Here we can construct two Gaussian surfaces. Electric field lines goes through the two Gaussian end caps in the outward direction. The field line do not goes through the curved surface. there is no electric flux through the curved Gaussian surface.

therefore applying Gauss's law

or,

or,

or,

Similarly an another identical sheet of opposite charge is brought closer near the previous one. Diagram is shown below

Between the two plates thew electric field will be twice of each plate.

i.e.

and the field will directed from +ve charged plate to -ve charged plate