Two 2.0-cm-diameter disks spaced 2.0 mm apart from a parallel-plate capacitor. The electric field between the disks is 5.0 x 10^5 V/m.
a) What is the voltage across the capacitor?
b) How much charge is on each disk?
c) An electron is launched from the negative plate. It strikes the positive plate at a speed of 2.0 x 10^7 m/s. What was the electron's speed as it left the negative plate?