Answer Happy

Figure 2 shows a cross sectional view on a diametral plane of two concentric hollow metal spheres. A magnetic field B is applied perpendicularly to the plane of the figure and a p.d. of 50 V is maintained between the spheres and, the inner one being positive with respect to the outer. The dashed line shows the path of an electron of energy 100 electron-volts. If the magnetic field is reversed, estimate the p.d. which must applied between the spheres in order to keep the electron moving in the same path. (28 marks) p.d. = potential difference Figure 2