an electron with a speed of 5x10^6 m/s is injected into a parallel plate apparatus, in a vacuum, through a hole in the positive plate. The electron collides with the negative plate at 1x10^6 m/s. What is the potential difference between the plates?
The Attempt at a Solution
I’m not quite sure what to do... i tried finding kinetic energy and setting it equal to the energy in the plates but that gave me a small answer (i checked in the back the answer is 68V)