Suppose the conducting spherical shell in the figure below carries a charge of 3.80 nC and that a charge of -2.20 nC is at the center of the sphere. If a = 1.80 m and b = 2.30 m, find the electric field at the following. (a) r = 1.50 m magnitude N/C direction (b) r = 2.20 m (c) r = 2.50 m magnitude N/C direction (d) What is the charge distribution on the sphere? inner surface nC outer surface nC