Given the surface charge density,ρs =2μ c/m2 , exsisting in region ρ=0.2m, z=0, find E at (a) PA(ρ=0, z=0.5); (b) PB(ρ=0, z=-0.5). Show that (c) the field along the z axis reduces to that of an infinite sheet charge at small values of z; (d) the z axis field reduces to that of a point charge at large values of z.