3-(4 points). If it takes 50 J of energy to move 10 C of charge from point A to point B, what is the magnitude of the potential difference between points A and B? 3b-(10 points). Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions. The wires are separated by 20 cm. At what point between the two wires do they produce the same strength magnetic field?