''ε''<sub><small>0</small></sub> მნიშვნელობა მოიცემა
:<math> \varepsilon_0 =\frac {1}{\mu_0 c_0c^2}</math> = {{gaps|8.854|187|817}}...×1085×10<sup>−12</sup> A[[ამპერი|ა]]·s[[წამი|წმ]]/(V[[ვოლტი|ვ]]·m[[მეტრი|მ]]) = {{gaps|8.854|187|817}}...×10<sup>−12</sup> F/m
სადაც ''c'' არის [[სინათლის სიჩქარე]] [[ვაკუუმი|ვაკუუმში]], ხოლო ''μ''<sub><small>0</small></sub> არის მაგნიტური მუდმივა.
where ''c''<sub>0</sub> is the [[speed of light in vacuum]] and [[vacuum permeability|''μ''<sub><small>0</small></sub>]] is the magnetic constant or vacuum permeability.
==Value==
The value of ''ε''<sub><small>0</small></sub> is ''defined'' by the formula
:<math> \varepsilon_0 =\frac {1}{\mu_0 c_0^2}</math>
where ''c''<sub>0</sub> is the [[speed of light in vacuum]],<ref>Quote from NIST: "Current practice is to use ''c''<sub><small>0</small></sub> to denote the speed of light in vacuum according to [[ISO 31]]. In the original Recommendation of 1983, the symbol ''c'' was used for this purpose." See [http://physics.nist.gov/Pubs/SP330/sp330.pdf NIST ''Special Publication 330'', Appendix 2, p. 45 ]</ref> and ''μ''<sub><small>0</small></sub> is the parameter that international Standards Organizations call the "[[vacuum permeability|magnetic constant]]" (commonly called vacuum permeability). Since ''μ''<sub><small>0</small></sub> has the ''defined'' value 4π × 10<sup>−7</sup> H m<sup>−1</sup>,<ref>See the last sentence of the [http://physics.nist.gov/cuu/Units/ampere.html NIST definition of ampere].</ref> and ''c''<sub>0</sub> has the ''defined'' value {{gaps|299|792|458}} m·s<sup>−1</sup>,<ref>See the last sentence of the [http://physics.nist.gov/cuu/Units/meter.html NIST definition of meter].</ref> it follows that ''ε''<sub><small>0</small></sub> has a ''defined'' value given approximately by
:''ε''<sub><small>0</small></sub> ≈ {{gaps|8.854|187|817}}... × 10<sup>−12</sup> [[Farad|F]]·m<sup>−1</sup> (or [[Ampere|A]]<sup>2</sup>·[[second|s]]<sup>4</sup>·[[kilogram|kg]]<sup>−1</sup>·m<sup>−3</sup> in [[SI base unit]]s, or [[Coulomb|C]]<sup>2</sup>·[[Newton (unit)|N]]<sup>−1</sup>·m<sup>−2</sup> or [[Coulomb|C]]·[[Volt|V]]<sup>−1</sup>·m<sup>−1</sup> using other SI coherent units).<ref name="NIST" /><ref>A summary of the definitions of ''c''<sub>0</sub>, ''μ''<sub><small>0</small></sub> and ''ε''<sub><small>0</small></sub> is provided in the 2006 CODATA Report: [http://physics.nist.gov/cuu/Constants/codata.pdf CODATA report, pp. 6-7]</ref>
The ellipsis (...) does not indicate experimental uncertainty, but the arbitrary termination of a [[Irrational_number#Decimal_expansions|nonrecurring decimal]]. The historical origins of the electric constant ''ε''<sub><small>0</small></sub>, and its value, are explained in more detail below.
Alternatively, ''ε''<sub><small>0</small></sub> can be expressed as <!-- Would be useful to indicate why this would be a useful representation - calculation of electron orbitals? -->
:''ε''<sub><small>0</small></sub> ≈ {{gaps|1.418|597|2}}... × 10<sup>−39</sup> [[Coulomb|C]]<sup>2</sup>·[[Electron volt|eV]]<sup>-1</sup>·nm<sup>−1</sup>.
The view (sometimes encountered) that ''ε''<sub><small>0</small></sub> is a physical constant that describes a physical property of a realizable "vacuum" is incorrect. Rather, ''ε''<sub><small>0</small></sub> is a measurement-system constant introduced and defined as a result of international agreement. The value allocated to ''ε''<sub><small>0</small></sub> relates to the velocity of light in a ''reference situation'' or benchmark, sometimes called [[free space]], used as a baseline for comparison of measurements made in all types of real media. The physical properties of realizable vacuums such as [[outer space]], [[ultra-high vacuum]], [[QCD vacuum]] or [[vacuum state|quantum vacuum]] are experimental and theoretical matters, separate from ''ε''<sub><small>0</small></sub>. The meaning and value of ''ε''<sub><small>0</small></sub> are [[metrology]] issues, not issues about properties of realizable vacuums. This potential for confusion is why many Standards Organizations now prefer to use the name "electric constant" for ''ε''<sub><small>0</small></sub>.
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