2.23 Given the surface charge density, p、 = 2 µC/m², existing in the region p < 0.2 m, z=0, find E at (a) PA(p = 0, z = 0.5); (b) Pß(p = 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. 2