(Jackson Problem 4.10) Two concentric spheres of inner and outer radii a and b, respectively, carry charges :le. The empty space between the spheres is half-filled by a hemispherical shell of dielectric (of permittivity e), as shown in the gure. (a) Find the electric field everywhere between the spheres. (b) Calculate the surface charge distribution on the inner sphere. (c) Calculate the polarization-charge density induced on the surface of the dielectric at r = a