Two fixed charges, -4.0 μC and -5.0 μC, are separated by a certain distance.
(a) Is the net electric field at a location halfway between the two charges (1) directed toward the -4.0 μC charge., (2) zero, or (3) directed toward the -5.0 μC charge? Why?
(b) If the charges are separated by 20 cm, calculate the magnitude of the net electric field halfway between the charges?