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Electronvolt (eV)

Quantity: energy · Category: Energy

The electronvolt is the kinetic energy gained by a single electron accelerated through an electric potential difference of one volt. It is a convenient unit for atomic- and particle-scale energies: photon energies in spectroscopy, ionization energies, and semiconductor band gaps are all routinely expressed in electronvolts rather than joules.

Relation to SI

1 eV = 1.602176634×10⁻¹⁹ J exactly

Examples

  • Visible-light photons carry ≈ 1.8–3.1 eV each
  • Ionization energy of hydrogen = 13.6 eV
  • Semiconductor band gaps are quoted in eV