A hollow conducting sphere has an internal radius of r1 = 1. 9 cm and an external radius of r2 = 3. 1 cm. The sphere has a net charge of Q = 1. 9 nC. a) What is the magnitude of the electric field in the cavity at the center of the sphere, in newtons per coulomb?

b) What is the magnitude of the field, in newtons per coulomb, inside the conductor, when r1 < r < r2?

c) What is the magnitude of the field, in newtons per coulomb, at a distance r = 5. 9 m away from the center of the sphere?