A problem of practical interest is to make a beam of electrons turn a 90? corner. This can be done with the parallel-plate capacitor shown in FIGURE P23.54. An electron with kinetic energy 3.0 × 10^-17J enters through a small hole in the bottom plate of the capacitor.

a. Should the bottom plate be charged positive or negative relative to the top plate if you want the electron to turn to the right? Explain.b. What strength electric field is needed if the electron is to emerge from an exit hole 1.0 cm away from the entrance hole, traveling at right angles to its original direction?

c. What minimum separation d_min must the capacitor plates have?

d Electrons FIGURE P23.54