# Electronvolt

**the electronvolt** or **electron volt** (unit symbol eV) is a unit of the energy (symbol *E*). Legally correctly and standard only the designation is “electron volt”, sees law over units in the measurement and DIN 1301 in Germany.

## Table of contents |

## definition

1 eV = 1.602 176,462 (63) · 10^{,-19} J

1 electronvolt is the energy, which receives a particle with the charge 1 e (elementary charge), ifit the tension of 1 V freely in the vacuum goes through. The energy can be transferred simply in SI - system (to the unit joule), by one for the letter *e* the elementary charge 1,602·10^{,-19} coulombs uses.

## use

the electronvoltas practical unit in atomic physics and related fields of activity one uses. In experimental elementary particle physics the electronvolt became generally accepted as „handy “unit. Both the proper mass of elementary particles and the energy, on it in Elemantarteilchenbeschleunigern (synchrotron)are brought, in (multiples of) electronvolts are indicated. The conversion happens with the help of the well-known equation from special relativity theory

- < math> E = m \ cdot c^2< /math>,

whereby <math> E< /math> for the energy, <math> m< /math> for the mass and <math> C< /math> for the vacuum speed of light stands.

Common decimal multiple electronvolts are

- keV (Kilos - electron volts)
- MeV (mega - electron volt) ( the rest energy of an electron is about 0.5 MeV)
- GeV (Giga - electron volts) ( the rest energy of a proton is about 0.9 GeV)
- TeV (Tera - electron volt)

as comparison:The fission products of a nuclear fission have a kinetic energy of together about 200 MeV. A typical molecule in the atmosphere has a kinetic energy (thermal energy) of approximately 0.03 eV. The photons of visible light (red) have an energy of approximately2 eV.

In order to convert the middle kinetic energy of the particles of an ideal gas into the temperature of the gas, one multiplies by <math> \ frac {2} {3} \ cdot 11,605< /math> K /eV; see also Maxwell Boltzmann distribution.