Astrophysics (Index)About

electron volt

(eV)
(very small unit of energy)

The electron volt (eV) is a unit of energy, much smaller than a joule or erg, defined to be the amount of energy necessary to move an electron through an electric field to a point where the field has an electric potential one volt more negative. Based upon the current (since 2019) SI definitions, this is exactly 1.602176634 × 10-19 joules (which is roughly 1.6 × 10-12 ergs). The electron volt is commonly used in atomic-scale physics. They are commonly used when citing the energy of individual photons: EMR photon energy is directly proportional to its frequency, and is commonly cited when characterizing very-high-frequency/short-wavelength EMR such as X-rays and gamma rays. Electron volts are also commonly used to cite energy differences necessary for atomic excitation or ionization. They are also commonly used for particle kinetic energy (e.g., for cosmic rays), and for particle rest mass (according to the mass/energy equivalence, e=mc², i.e., 1.782662×10-36 kg).

The electron volt also serves as a unit for other quantities that have a direct relation to energy, for example, as a large unit of temperature often used for plasma, corresponding to 1.160451812×104 K (as per the equation e=kBT).


(physics,unit,energy,EMR,temperature,mass)
Further reading:
https://en.wikipedia.org/wiki/Electronvolt
https://en.wikipedia.org/wiki/Elementary_charge
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ev.html
https://physics.nist.gov/cgi-bin/cuu/Value?evj
https://www.bipm.org/en/publications/si-brochure

Referenced by pages:
alpha particle
AXIS
Brackett series
CASA-MIA
Chandra X-ray Observatory (CXO)
Cherenkov Telescope Array (CTA)
CNO cycle
Compton telescope
cosmic neutrino background (CNB)
cosmic rays (CR)
electromagnetic spectrum
electron (e-)
energy
eROSITA
EUSO-SPB
fuzzy dark matter (FDM)
gamma rays (GR)
GRB 190114C
GZK limit
High-altitude Water Cherenkov Observatory (HAWC)
Humphreys series
hydrogen (H)
ionization potential
ionized hydrogen (HII)
ionizing radiation
K-line
Kvant 1
Lee-Weinberg bound
Lyman continuum (LyC)
Lyman series (L)
Lyman-Werner photon
mass
Milagro
neutrino (ν)
Oh-My-God Particle
pair production
pair telescope
Paschen series
Pfund series
photoionization
photon
photon energy
Pierre Auger Observatory (PAO)
rare designator prefixes
Rydberg constant (RH)
Rydberg unit
solar energetic particle (SEP)
solar neutrino
spectral energy distribution (SED)
Spektr-RG (SRG)
Strömgren sphere
STROBE-X
sub-GeV dark matter
Telescope Array Project (TA)
THESEUS
triple alpha process
Uhuru
ultra-high-energy gamma rays (UHEGR)
very-high-energy gamma rays (VHEGR)
VHE
X-ray

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