Elektronvolt: Verskil tussen weergawes
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RAM (besprekings | bydraes) Nuwe blad: Die '''elektronvolt''' (simbool '''eV''') is 'n eenheid van energie. Dit is die hoeveelheid kinetiese energie wat 'n enkele onverbonde elektron verkry as dit deur 'n [[Elektr... |
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: 1 eV = 1.602 176 53 e<sup>−19</sup> [[joule|J]]. <ref>Peter J. Mohr en Barry N. Taylor, CODATA recommended values of the fundamental physical constants: 2002, Reviews of Modern Physics, January 2005, volume=77 bladsye=1–107, [http://www.atomwave.org/rmparticle/ao%20refs/aifm%20refs%20sorted%20by%20topic/other%20rmp%20articles/CODATA2005.pdf PDF] afgelaai op 2006-07-01, 'n In diepte bespreking oor hoe die CODATA konstantes gekies en bepaal is.</ref> (of ongeveer 0.160 [[atto|a]]J) |
: 1 eV = 1.602 176 53 e<sup>−19</sup> [[joule|J]]. <ref>Peter J. Mohr en Barry N. Taylor, CODATA recommended values of the fundamental physical constants: 2002, Reviews of Modern Physics, January 2005, volume=77 bladsye=1–107, [http://www.atomwave.org/rmparticle/ao%20refs/aifm%20refs%20sorted%20by%20topic/other%20rmp%20articles/CODATA2005.pdf PDF] afgelaai op 2006-07-01, 'n In diepte bespreking oor hoe die CODATA konstantes gekies en bepaal is.</ref> (of ongeveer 0.160 [[atto|a]]J) |
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Die elektronvolt as eenheid word deur die [[SI]] aanvaar (maar nie aangemoedig nie). Dit word algemeen gebruik in [[Vastetoestandfisika|Vastetoestand-]], [[Kernfisika|Kern-]] en [[partikelfisika]], dikwels saam met die [[SI#SI-voorvoegsels|voorvoegsels]] m, k, M, G of T. |
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The unit electronvolt is accepted (but not encouraged) for use with [[SI]]. It is widely used in [[Solid-state physics|solid state]], [[Atomic physics|atomic]], [[Nuclear physics|nuclear]], and [[particle physics]], often with [[SI prefix|prefixes]] m, k, M, G or T. In a recorded lecture from 1961 [[Richard Feynman]] apologised to his students for this failure by atomic physicists to use the appropriate SI unit (which would be the [[atto]]joule): |
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:''"Nearly a third of what you have to learn consists of different ways of measuring the same thing, and I apologize for it ... A single atom is such a small thing that to talk about its energy in joules would be inconvenient. But instead of taking a definite unit in the same system (like 10{{e|-20}} J), [physicists] have unfortunately chosen, arbitrarily, a funny unit called an electronvolt (eV) ... I am sorry that we do that, but that's the way it is for the physicists."'' <ref>[http://home.att.net/~numericana/answer/feynman.htm Transcription of part of a 1961 lecture by Richard Feynman]</ref> |
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[[Ionisasie energie]]ë en ander atoomeienskappe word dikwels aangehaal in terme van elektronvolt, veral in ouer tekste. |
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In [[chemistry]], it is often useful to have the molar equivalent, that is the kinetic energy that would be gained by a [[mole (unit)|mole]] of electrons passing through a potential difference of one volt. This quantity is equal to [[1 E4 J|96.48538(2)]] [[Joule per mole|kJ/mol]]. [[Ionization energy|Ionization energies]] and other atomic properties are often quoted in electronvolts, especially in older texts. |
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==Using electronvolts to measure mass== |
==Using electronvolts to measure mass== |
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[[Albert Einstein]] reasoned that energy is equivalent to [[mass]], as famously expressed in the [[mass-energy equivalence]] formula ''E'' = ''mc''² (1.0000 [[kilogram|kg]] = 89.876 [[petajoule|PJ]]). It is thus common in particle physics, where mass and energy are often interchanged, to use eV/''c''² or even simply eV as a unit of mass. |
[[Albert Einstein]] reasoned that energy is equivalent to [[mass]], as famously expressed in the [[mass-energy equivalence]] formula ''E'' = ''mc''² (1.0000 [[kilogram|kg]] = 89.876 [[petajoule|PJ]]). It is thus common in particle physics, where mass and energy are often interchanged, to use eV/''c''² or even simply eV as a unit of mass. |
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Wysiging soos op 19:12, 29 Mei 2007
Die elektronvolt (simbool eV) is 'n eenheid van energie. Dit is die hoeveelheid kinetiese energie wat 'n enkele onverbonde elektron verkry as dit deur 'n elektrostatiese potensiaalverskil van een volt in 'n vakuum versnel word. In ander woorde gestel is dit gelyk aan een volt (1 volt = 1 joule per coulomb) vermenigvuldig met die lading van 'n enkele elektron.
'n Elektronvolt is 'n baie klein hoeveelheid energie:
Die elektronvolt as eenheid word deur die SI aanvaar (maar nie aangemoedig nie). Dit word algemeen gebruik in Vastetoestand-, Kern- en partikelfisika, dikwels saam met die voorvoegsels m, k, M, G of T.
Ionisasie energieë en ander atoomeienskappe word dikwels aangehaal in terme van elektronvolt, veral in ouer tekste.