Three nested hollow spheres have the same center. The innermost sphere has a radius of 2 cm and carries a uniformly distributed charge of 6 nC (1 nC = 1×10−9 C). The middle sphere has a radius of 5 cm and carries a uniformly distributed charge of −4 nC. The outermost sphere has a radius of 10 cm and carries a uniformly distributed charge of 8 nC. (a) What is the magnitude of the electric field at a distance of 1 cm from the center? (b) What is the magnitude of the electric field at a distance of 4 cm from the center? (c) What is the magnitude of the electric field at a distance of 9 cm from the center?