1. The problem statement, all variables and given/known data An electron beam travels from an electrode on the right to one on the left. Which end of the electron beam is at a higher potential? 2. Relevant equations 3. The attempt at a solution My reasoning was that if the electron beam is moving from right to left, then the current's direction is from left to right. Current usually moves from the positive to the negative (like in a battery). The positive terminal of a battery is at the higher potential. Therefore, the the right end of the electron beam is at the higher potential. But I really don't know, that was more of a guess than anything. Was my reasoning completely flawed?