magnitude of the electric field at the electron's location? 3. (Electric field, Prob. 15.29, 2.5 points) Three charges, +2.5 JC, -4.8 uC, and -6.3 uC are located at (-0.20 m, 0.15 m), (0.50 m, -0.35 m), and (-0.42 m, -0.32 m), respectively. What is the electric field at the origin? 4. (Electric field, Prob. 15.30, 2.0 points) Two charges of +3.0 uC and +6.0 uC are 40 art