Two 2.00cm -diameter disks spaced 1.80mm apart form a parallel-plate capacitor. The electric field between the disks is 4.80×10^5 .
a.) How much charge is on each disk?
b.)An electron is launched from the negative plate. It strikes the positive plate at a speed of 2.10×10^7 m/s . What was the electron's speed as it left the negative plate?