Explain this statement: “In a static situation, the electric field at the surface of a conductor can have no component parallel to the surface because this would violate the condition that the charges on the surface are at rest.” Would this same statement be valid for the electric field at the surface of an insulator?
I think it'd be valid, because electric field parallel to the surface might cause surface currents. However, inside an insulator we can't use the fact that field inside is zero; which is key to proving the expression for electrostatic pressure in which we safely assume that field is only normal to the surface of the conductor
I'm slightly confused, does this have something to do with polarisation? Please explain.