A hollow metal sphere has inner radius a, outer radius b, and conductivity . The current I is radially outward from the inner surface to the outer surface. Find an expression for the electric field strength inside the metal as a function of the radius r from the center Express your answer in terms of the variables I, , r, and appropriate constants. E= I 042 Submit Previous Answers Part B Correct Evaluate the electric field strength at the inner surface of a copper sphere if a = 0.70 cm, b = 2.4 cm, and I = 21 A Express your answer to two significant figures and include the appropriate units. E= Value Units Submit Request Answer Part C ? Evaluate the electric field strength at the outer surface of a copper sphere if a = 0.70 cm, b = 2.4 cm, and I = 21 A. Express your answer to two significant figures and include the appropriate units. E= Value Units W ?