An electron volt (eV) is the amount of kinetic energy gained by an electron as it passes through an electric potential difference of 1 Volt. It has the value:

1 eV = 1.602 176 53(14)x10^{-19} Joules

with the measurement error in the decimal places in brackets. Given its small value, energies are often expressed as mega-electron volts (1 MeV = 10^{6} eV) and giga-electron volts (1 GeV = 10^{9} eV).

Although not a standard unit of measurement, it is typically used to measure the energies of elementary particles. In addition, since mass is related to energy through Einstein’s famous equation, *E = mc ^{2}*, the

All material is © Swinburne University of Technology except where indicated.