# electronvolt

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## electronvolt

a unit of energy equal to the work done on an electron accelerated through a potential difference of 1 volt. 1 electronvolt is equivalent to 1.602 × 10

^{--19}joule.## Electronvolt

A unit of energy used for convenience in atomic systems. Specifically, it is the change in energy of an electron, or of any particle having a charge numerically equal to that of an electron, when it is moved through a difference of potential of 1 mks volt. Its value (in mks units) is obtained from the equation *W* = *qV*, where *W* is energy in joules, *q* the charge in coulombs, and *V* the potential difference in volts. For a potential difference of 1 volt and the electronic charge of 1.602 × 10^{-19} coulomb, the electronvolt is 1.602 × 10^{-19} joule. *See* Electron, Ionization potential

## electronvolt

(i-lek-tron-**vohlt**) Symbol: eV. A unit of energy equal to the energy acquired by an electron falling freely through a potential difference of one volt. It is equal to 1.6022 × 10

^{–19}joule. High-energy electromagnetic radiation is usually referred to in terms of the energy of its photons: a photon energy of 100 eV is equivalent to a radiation frequency of 2.418 × 10

^{16}hertz. The energies of elementary particles are usually quoted in eV; their rest masses are generally referred to in terms of their energies in eV.

## electronvolt

[i′lek‚trän ‚vōlt] (physics)

A unit of energy which is equal to the energy acquired by an electron when it passes through a potential difference of 1 volt in a vacuum; it is equal to (1.60217646±0.00000006) × 10

^{-19}volt. Abbreviated eV.