A -3.41 nC point charge is located at the center of a conducting spherical shell. The shell has an inner radius of 2 m, an outer radius of 4 m, and a charge of 8.73 nC. What is the magnitude of the electric field at r = 1 m, r = 2 m, r = 3 m? What is the surface charge density on the outside surface of the shell?