4. A series of equipotential lines are shown right. Points A- D are shown. The shaded areas are conductors with a net charge. Point A has a potential of 30 V, point B 35 V, point C -10 V, and point D 0 V. The distance between points B and C is 7.5 mm.
(i) An electron travels from A to B, and then to C, and then to D. What is the work done on the electron by the field, as measured in eV?
(ii) What is the magnitude of the electric field between points B and C?