A uniform electric field of 2000 N/C is in a direction 600 from the x-axis. A charge of -1.20 mC starts from the origin O and moves in a straight line to a point A with coordinates (4.00 mm, 0.00 mm) and from there in a straight line to the point B (4.00 mm, 4.00 mm), and from there, back to the origin, again in a straight line. Draw a diagram and calculate the work done in each leg of the journey, OA, AB and BO. Show, by adding these three, that the total work done is zero. If point A is at a potential of 1000 V, calculate the potential at B and at the origin.