1. The problem statement, all variables and given/known data Drawing of the Problem An electron rests on plate A and is accelerated by a 400V Plate (B). From there, Calculate the Maximum Voltage a 3cm plate (C) can be charged before the electron makes contact with the plate. Directly opposite Plate (C), is a +100V Charged Plate D. 2. Relevant equations Electrostatic forumulas 3. The attempt at a solution I assume the first step would be to calculate the velocity at which the electron leaves Plate B. Voltage is 400V, and Ep can be calculated using Ep = q * V Ep = (1.60 * 10^-19) * 400 = 6.4 * 10^-17 Ek = Ep Ek = 6.4 * 10^-17 1/2mV^2 = 6.4 * 10^-17 V = 1.2 * 10^7 Is that correct for the velocity when the electron leaves Plate B? After this, I have to calculate the maximum Voltage. That really isnt a massive problem as I can do that part by myself. The part that confuses me is that now I have a 400V current in the plate A pulling my electron back. Can someone show me how id do that?