A thin, horizontal, 10-cm-diameter copper plate is charged to 3.5nC. If the electrons are uniformly distributed on the surface, what are the strengths and direction of the electric field (6 points)
a. 0.1 mm above the center of the top surface of the plate?
b. at the plate's center of mass?
c. 0.1 mm below the center of the bottom surface of the plate?