Q3. An insulating sphere of radius a is concentric with an uncharged conducting hollow sphere, whose inner and outer radii are b and c. If the insulating sphere has a uniform charge density p and a total charge Q, (a) find the magnitude of the electric field in the regions r < a, a < r < b, b < r < c, and r > c. (b) Determine the induced charge per unit area on the inner and outer surfaces of the hollow sphere.