Electron Volt

The work done accelerating an Electron through a potential difference of 1 Volt

$$1\text{ eV}=1.602\times 10^{-19}\text{ J}(=(1e)(1V))$$

also keV ($10^3$), MeV ($10^6$), GeV ($10^9$), TeV ($10^{12}$), PeV ($10^{15}$)