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Electronvolt (eV)

Quantity: Energy · Category: Non-SI

The electronvolt is a unit of energy equal to the kinetic energy gained by a single electron accelerating through one volt. It is the standard energy unit in atomic, nuclear and particle physics, where joules are impractically large.

Relation to SI

1 eV = 1.602176634×10⁻¹⁹ J (exact)

Examples

  • A photon of visible red light carries about 1.8 eV.
  • Chemical bonds store a few eV per molecule.
  • Particle accelerators reach trillions of eV (TeV).