Negative charge –Q is distributed uniformly over the surface of a thin spherical insulating

shell with radius R.

Part A Calculate the magnitude of the force that the shell exerts on a positive point charge q

located a distance r>R from the center of the shell (outside the shell).

Express your answer in terms of the variables q, Q, r, R, and constants π and ϵ0.

Part B Find the direction of the force that the shell exerts on a positive point charge q located a

distance r>R from the center of the shell (outside the shell).

Part C Calculate the magnitude of the force that the shell exerts on a positive point charge q

located a distance r
Express your answer in terms of the variables q, Q, r, R, and constants π and ϵ0.