A -5-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 +6 nC. (Let the radially outward direction be positive.) (a) What is the electric field at r = 1 m? (Indicate the direction with the sign of your answer.) (b) What is the electric field at r = 3 m? (Indicate the direction with the sign of your answer.) (c) What is the electric field at r = 5 m? (Indicate the direction with the sign of your answer.) (d) What is the surface charge distribution, ?, on the outside surface of the shell? (Indicate the direction with the sign of your answer.)