b 5. Two concentric conducting spherical shells of radii a and b have charges of equal magnitude and opposite sign as shown above. a) Determine the electric field at a distance r from the center Give separate expressions for r< a, a b. b) Determine the electric potential at r = b and at r = a, taking the potential equal to zero at infinity.

b 5. Two concentric conducting spherical shells of radii a and b have charges of equal magnitude and opposite sign as shown above. a) Determine the electric field at a distance r from the center Give separate expressions for r< a, a b. b) Determine the electric potential at r = b and at r = a, taking the potential equal to zero at infinity.