Electronvolt
Encyclopedia : E : EL : ELE : Electronvolt
The electronvolt (symbol eV, or, rarely and incorrectly, ev) is a unit of energy. It is the amount of kinetic energy gained by a single unbound electron when it passes through an electrostatic potential difference of one volt, in vacuum. In other words, it's equal to one volt times the magnitude of charge of a single electron. The one-word spelling is the modern recommendation although the use of the earlier electron volt still exists.
One electronvolt is a very small amount of energy:
For example, a typical magnetic confinement fusion plasma is 15 keV, or 174 megakelvins.Electronvolts and time
A very brief length of time can be measured with eV. The uncertainty principle gives [ E \, \cdot \, t \ \ \frac]. A time can correspond to an energy, and when the length of time is very brief (less than an attosecond), the measure is less signficant for the observer if expressed in seconds. The conversion is carried out by :
[\frac \frac = \frac \ \mbox\cdot\mbox} \mbox} = 3.29101135938 \times10^ \mbox]
This kind of length is encountered in half-lifes of exotic kernels. For exemple, the half-life of the 8C is 230keV (1.43×10-21 s).
See also
External links
- [BIPM's definition of the electronvolt]
- http://physics.nist.gov/cuu/Constants physical constants reference; CODATA data
- [Conversion of eV in other units]
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