1. The problem statement, all variables and given/known data The device has two parallel plates, one positively charged and one negatively. The positive plate has a hole to allow electrons to fire out of it. b) How can the device be modified to accelerate protons? c) How does the escape velocity of a proton compare to that of an electron, if the electric field were the same? Explain. 2. Relevant equations a = qε/m 3. The attempt at a solution Part c is what I'm unsure about. Are they assuming that I've modified the device, but the electric field has the same magnitude? If so, my educated guess is as follows: The particles have equal but opposite charges and experience the same field, but a proton has a larger mass and will be accelerated less before exiting the device; therefore, it will have a lower exit speed. On the other hand, assuming the device has not been modified, the proton would still have a lower exit speed (probably won't exit at all) because it's attracted to the negative plate.