what is the difference between electron volts and proton volts?
Nothing, except for the sign
A proton is approximately 1800 times more massive than an electron. Therefore that factor comes into the size comparison.
Because and electron volt is V*(carge on an electron), and a proton volt is V*(charge on a proton), the only difference is in the charge, so it's only a sign change. One electron volt equals -1 proton volts.
So far, everyone in this thread has been wrong. Please be careful, folks, when posting help that you don't know for sure is correct!
The electron volt is a unit of energy, NOT CHARGE. The electron volt is the energy gained by an electron when moving through a potential difference of one volt. A proton would gain the exact same energy when moving through such a potential; it would just travel in the opposite direction.
The electron volt and the proton volt represent the same amount of energy, since the charge on the two particles is the same in magnitude.
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