Electronvolt

Because a joule is such a large unit of energy, compared to the energy of an electron, when we’re measuring the energy that an electron holds, it’s not very convenient to measure everything in joules.

To fix that, we use electronvolts, which measure a much smaller quantity of energy, so we have more of them for every joule.

Converting electronvolts to joules

\text{joules}=\text{electronvolts}\div(1.6\times10^{-19})

Converting joules to electronvolts

\text{electronvolts}=\text{joules}\times(1.6\times10^{-19})