A solid insulating sphere of radius R has a nonuniform charge density that varies with r according to the expression ρ = Ar 2, Where A is a constant and r<R is measured from the centre of the sphere.
(a). Show that the magnitude of the electric field outside (r > R) the sphere is
(b). Show that the magnitude of the electric field inside (r < R) the sphere is
Note: The volume element dV for a spherical shell of radius r and thickness dr is equal to
