Two spherical shells have a common center. A -2.50 \times 10- C charge is spread uniformly over the inner shell, which has a radius of 0.050 m. A 5.00 \times 10-C charge is spread uniformly over the outer shell, which has a radius of 0.15 m. Find the magnitude and direction of the electric field at a distance (measured from the common center) of(a) 0.20 mE =(b) 0.10 m,E =(c) 0.025 m.E =