The two metal spheres of radius a have equal but opposite sign of charges as shown in figure below. The centers are separated by distance 4a. a a A O a) Determine the electric field in magnitude and direction, at any arbitrary point P inside the sphere. (5 pts.) b) Determine the net electric field E, in magnitude and direction, at the midpoint 0. (Hint: you can apply Gauss' Law ) (5 pts.) c) Find the electric potential Va at a point A at a distance 3a/2 from the center of the left sphere. (5 pts.) d) Calculate the electric force F on an electron (e) when it is put at center 0. (5 pts.)