A convenient energy unit, particularly for atomic and nuclear processes, is the energy given to an electron by accelerating it through 1 volt of electric potential difference. The work done on the charge is given by the charge times the voltage difference, which in this case is:
Energies in Electron Volts
Room temperature thermal energy of a molecule..................................0.04 eV
Visible light photons....................................................................................1.5-3.5 eV
Energy for the dissociation of an NaCl molecule into Na+ and Cl- ions:................................................................................................................4.2 eV
Ionization energy of atomic hydrogen ........................................................13.6 eV
Approximate energy of an electron striking a color television screen...............................................................................................................20,000 eV
High energy diagnostic medical x-ray photons...............................200,000 eV (=0.2 MeV)
Typical energies from nuclear decay:
(1) gamma..................................................................................................0-3 MeV
(2) beta.......................................................................................................0-3 MeV
(3) alpha....................................................................................................2-10 MeV
Cosmic ray energies ........................................................................1 MeV - 1000 TeV
