Електронволт — разлика између измена
Садржај обрисан Садржај додат
Спашавам 1 извора и означавам 0 мртвим. #IABot (v2.0beta8) |
. |
||
Ред 1:
{{рут}}{{short description|Јединица енергије}}
[[Datoteka:Light_spectrum.svg|right|frame|'''Frekvencija fotona nasuprot energije čestice u elektronvoltima'''. Energija fotona varira sa frekvencijom fotona, što je vezano konstantom brzine svjetlosti. Ovi kontrasti sa masivnim česticama od kojih energija zavisi od svoje brzine i ostatka mase.<ref>{{Cite web |url=http://cbst.ucdavis.edu/education/courses/winter-2006-IST8A/ist8a_2006_01_09light.pdf |title=What is Light? |accessdate=22. 6. 2015 |archiveurl=https://web.archive.org/web/20131205005843/http://cbst.ucdavis.edu/education/courses/winter-2006-IST8A/ist8a_2006_01_09light.pdf |archivedate=5. 12. 2013 |url-status=dead }}</ref><ref>{{cite web|author = Elert, Glenn|url = http://hypertextbook.com/physics/electricity/em-spectrum/|title = The Electromagnetic Spectrum, The Physics Hypertextbook|publisher = Hypertextbook.com|accessdate = 2010-10-16}}</ref><ref>{{cite web|url = http://www.vlf.it/frequency/bands.html|title = Definition of frequency bands on|publisher = Vlf.it|accessdate = 2010-10-16}}</ref><br>
<br>
Legenda
{| border="0" id="38"
| id="41" |γ: [[Gama zračenje|Gama zrake]]
| id="44" |MIR: srednje infracrveno
| id="46" |HF: visoka frek.
|- id="49"
| id="50" |HX: Jake [[Rendgensko zračenje|X-zrake]]
| id="53" |FIR: daleko infracrveno
| id="55" |MF: srednja frek.
|- id="58"
| id="59" |SX: Blage X-zrake
| id="61" |[[Radiotalasi|Radiotalas]]
| id="64" |LF: niska frek.
|- id="67"
| id="68" |EUV: Ekstremne ultraljubičaste
| id="71" |EHF= ekstremno visoka frek.
| id="74" |VLF: veoma niska frek.
|- id="77"
| id="78" |NUV: [[Ultraljubičasto zračenje|Blizu ultraljubičastog]]
| id="81" |SHF= super visoka frek.
| id="84" |VF/ULF: zvučna frek.
|- id="87"
| id="88" |[[Svjetlost|Vidljivo svjetlo]]
| id="91" |UHF= ultra visoka frek.
| id="94" |SLF: super niska frek.
|- id="97"
| id="98" |NIR: Blizu [[Infracrveno zračenje|infracrvenog]]
| id="101" |VHF= veoma visoka frek.
| id="104" |ELF: ekstremno niska frek.
|- id="107"
| id="110" |Frek: [[Frekvencija]]
|}]]
'''Електронволт''', -{'''eV'''}-, је јединица [[енергија|енергије]] једнака [[кинетичка енергија|кинетичкој енергији]] коју задобије слободни [[електрон]] у вакууму проласком кроз потенцијалну разлику од једног [[волт]]а. Другим речима, то је један волт (1 волт = 1 [[џул]] по [[Кулон (јединица)|кулону]]) пута [[количина елементарног наелектрисања|наелектрисање једног електрона]] (у кулонима). Један електронволт је врло мала јединица енергије: 1 eV = 1,602 176 53(14){{e|−19}} [[Џул|J]].<ref>[http://physics.nist.gov/cuu/Constants/index.html CODATA Internationally recommended values of the Fundamental Physical Constants]</ref>
U [[Fizika|fizici]], elektronvolt<ref>[http://goldbook.iupac.org/E02014.html IUPAC Gold Book], p. 75</ref><ref>[http://www.bipm.org/en/si/si_brochure/chapter4/table7.html ''SI brochure''] {{Webarchive|url=https://web.archive.org/web/20120716204133/http://www.bipm.org/en/si/si_brochure/chapter4/table7.html |date=16. 7. 2012 }}<sup class="noprint Inline-Template"><span style="white-space: nowrap;">[''[[Wikipedia:Mrtav link|<span title=" since May 2015">dead link</span>]]'']</span></sup>, Sec. 4.1 Table 7</ref> (simbol '''eV'''; također se piše '''elektron volt''') jeste jedinica energije jednaka približno 160 zeptodžula (simbol zJ) ili <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6981160000000000000♠</span><span style="white-space:nowrap">1.6</span><span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">19</span></sup></span><span class="nowrap" contenteditable="false"></span> [[Džul|džula]] (simbol J). Po definiciji, to je količina energije dobijene (ili izgubljene) nabojem jednog [[Elektron|elektrona]] koji se pomjera kroz [[Električni potencijal|električnu potencijalnu razliku]] jednog [[Volt|volta]]. Tako je 1 [[volt]] (1 džul po [[Kulon|kulonu]] ili <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">7000100000000000000♠</span><span style="white-space:nowrap">1</span> J/°C</span>) pomnožen elementarnim nabojem (''e'', ili <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6981160217656499999♠</span><span style="white-space:nowrap">1.602<span style="margin-left:.25em">176</span><span style="margin-left:.25em">565</span></span>(35)<span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">19</span></sup> [[Kulon|C]]</span><span class="nowrap" contenteditable="false"></span>). Otuda je, jedan elektronvolt jednak <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6981160217656499999♠</span><span style="white-space:nowrap">1.602<span style="margin-left:.25em">176</span><span style="margin-left:.25em">565</span></span>(35)<span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">19</span></sup> [[Džul|J]]</span><span class="nowrap" contenteditable="false"></span>.<ref name="NIST">{{cite web|url = http://physics.nist.gov/constants|title = Fundamental Physical Constants from NIST}}</ref> Historijski, elektronvolt je bio standardna jedinica mjere kroz svoju koristivost u elektrostatičkom akceleratoru čestica zbog čestica sa nabojem ''q'' koji ima energiju <span class="nowrap" contenteditable="false">''E'' = ''qV''</span><span class="nowrap" contenteditable="false"></span> kroz prolazak kroz potencijal ''V''; ako se ''q'' uzima u cjelobrojnim jedinicama elementarnog naboja i terminalni prednapon u voltima, dobija se energija u eV.
Elektronvolt nije [[SI sistem|SI jedinica]], te je njegova definicija empirijska (za razliku od [[Litar|litra]], [[Svjetlosna godina|svjetlosne godine]] i ostalih takvih ne-SI jedinica), tako da njegova vrijednost u SI jedinicama mora biti dobijena eksperimentalno.<ref>{{cite web|url = http://physics.nist.gov/cuu/Units/outside.html|title = Definitions of the SI units: Non-SI units}}</ref> Kao elementarni naboj na kojem je zasnovan, on nije nezavisnog kvantiteta nego je jednak <span class="nowrap" contenteditable="false">1 <span class="sfrac nowrap" style="display:inline-block; vertical-align:-0.5em; font-size:85%; text-align:center;"><span style="display:block; line-height:1em; margin:0 0.1em;">J</span><span class="visualhide">/</span><span style="display:block; line-height:1em; margin:0 0.1em; border-top:1px solid;">C</span></span> <span class="nowrap">√<span style="border-top:1px solid; padding:0 0.1em;">2[[Planckova konstanta|''h'']][[Fine structure constant|''α'']] / [[Magnetic constant|''μ''<sub>0</sub>]][[Brzina svjetlosti|''c''<sub>0</sub>]]</span></span></span><span class="nowrap" contenteditable="false"></span>. To je opća jedinica energije u fizici, šire korištena u čvrstom stanju, [[Atomska fizika|atomskoj]], [[Nuklearna fizika|nuklearnoj]] i [[Fizika elementarnih čestica|fizici čestica]]. Često se koristi sa [[Prefiksi mjernih jedinica|metričkim prefiksima]] milli-, kilo-, mega-, giga-, tera-, peta- ili exa- (meV, keV, MeV, GeV, TeV, PeV i EeV respektivno). Tako meV stoji za milielektronvolt.
U nekim starijim dokumentima, i u imenu [[Bevatron]], simbol BeV se koristi, koji stoji za milijardu eV; to je ekvivalent za GeV.
{| class="wikitable" id="cx135" margin:0 0 1em 1em;" data-source="135" data-cx-weight="378" contenteditable="true" data-cx-draft="true"
! id="138" | Mjera
! id="140" | Jedinica
! id="142" | SI vrijednost jedinice
|- id="144"
| id="145" | Energija
| id="147" | eV
| id="149" | <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6981160217656499999♠</span><span style="white-space:nowrap">1.602<span style="margin-left:.25em">176</span><span style="margin-left:.25em">565</span></span>(35)<span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">19</span></sup> J</span>
|- id="151"
| id="152" | Masa
| id="154" | eV/''c''<sup>2</sup>
| id="156" | <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6964178266199900000♠</span><span style="white-space:nowrap">1.782<span style="margin-left:.25em">662</span></span><span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">36</span></sup> kg</span>
|- id="158"
| id="159" | Momentum
| id="161" | eV/''c''
| id="163" | <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6972534428600000000♠</span><span style="white-space:nowrap">5.344<span style="margin-left:.25em">286</span></span><span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">28</span></sup> kg⋅m/s</span>
|- id="165"
| id="166" | Temperatura
| id="168" | eV/''k''<sub>B</sub>
| id="170" | <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">7004116045050099999♠</span><span style="white-space:nowrap">11<span style="margin-left:.25em">604</span>.505</span>(20) K</span>
|- id="172"
| id="173" | Vrijeme
| id="175" | ''ħ''/eV
| id="177" | <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6984658211900000000♠</span><span style="white-space:nowrap">6.582<span style="margin-left:.25em">119</span></span><span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">16</span></sup> s</span>
|- id="179"
| id="180" | Udaljenost
| id="182" | ''ħc''/eV
| id="184" | <span class="nowrap" contenteditable="false"><span class="sortkey" style="display:none">6993197327000000000♠</span><span style="white-space:nowrap">1.973<span style="margin-left:.25em">27</span></span><span style="margin-left:0.25em;margin-right:0.15em">×</span>10<sup>−<span style="white-space:nowrap">7</span></sup> m</span>
|}
==Definition==
An electronvolt is the amount of kinetic energy gained or lost by a single [[electron]] accelerating from rest through an [[Voltage|electric potential difference]] of one [[volt]] in vacuum. Hence, it has a value of one [[volt]], {{val|1|u=J/C}}, multiplied by the electron's [[elementary charge]] ''e'', {{physconst|e|after=.}} Therefore, one electronvolt is equal to {{physconst|eV|after=.}}
The electronvolt, as opposed to the volt, is not an [[International System of Units|SI unit]]. The electronvolt (eV) is a unit of energy whereas the volt (V) is the derived SI unit of electric potential. The SI unit for energy is the joule (J).
==Mass==
By [[mass–energy equivalence]], the [[electronvolt]] is also a unit of [[mass]]. It is common in [[particle physics]], where units of mass and energy are often interchanged, to express mass in units of eV/''c''<sup>2</sup>, where ''c'' is the [[speed of light]] in vacuum (from [[Mass–energy equivalence|{{nowrap|1=''E'' = ''mc''<sup>2</sup>}}]]). It is common to simply express mass in terms of "eV" as a [[unit of mass]], effectively using a system of [[natural units]] with ''c'' set to 1.<ref>Barrow, J. D. "Natural Units Before Planck." Quarterly Journal of the Royal Astronomical Society 24 (1983): 24.</ref> The mass equivalent of {{val|1|u=eV/c2}} is
:<math>1\; \text{eV}/c^2 = \frac{(1.602\ 176\ 634 \times 10^{-19} \; \text{C}) \cdot 1 \; \text{V}}{(2.99\ 792\ 458 \times 10^8\; \text{m}/\text{s})^2} = 1.782\ 661\ 92 \times 10^{-36}\; \text{kg}.</math>
For example, an electron and a [[positron]], each with a mass of {{val|0.511|u=MeV/c2}}, can [[Annihilation|annihilate]] to yield {{val|1.022|u=MeV}} of energy. The [[proton]] has a mass of {{val|0.938|u=GeV/c2}}. In general, the masses of all [[hadron]]s are of the order of {{val|1|u=GeV/c2}}, which makes the GeV (gigaelectronvolt) a convenient unit of mass for particle physics:
:{{val|1|u=GeV/c2}} = {{val|1.78266192|e=-27|u=kg}}.
The [[unified atomic mass unit]] (u), almost exactly 1 gram divided by the [[Avogadro number]], is almost the mass of a [[hydrogen atom]], which is mostly the mass of the proton. To convert to electron volts, use the formula:
:1 u = {{val|931.4941|u=MeV/c2}} = {{val|0.9314941|u=GeV/c2}}.
== Коришћење електронволта за изражавање масе ==
Линија 20 ⟶ 102:
:1 PeV/c² = 1,783{{e|−21}} kg
:1 EeV/c² = 1,783{{e|−18}} kg
== Електронволт и енергија ==
Линија 60 ⟶ 138:
* <math>\hbar</math> = 6,582 118 89(26) x 10<sup>-16</sup> eV s
* <math>\hbar c</math> = 197,326 960 2(77) eV nm
== Види још ==
* [[Термодинамика]]
== Референце ==
Линија 71 ⟶ 146:
== Литература ==
{{refbegin|
* {{GreenBook3rd}}
* {{GreenBook2nd}}
{{refend}}
== Спољашње везе ==
{{Commons category|Electronvolt}}
* -{[https://web.archive.org/web/20041204045317/http://www1.bipm.org/en/si/si_brochure/chapter4/table7.html BIPM's definition of the electronvolt]}-
* -{[http://physics.nist.gov/cuu/Constants physical constants reference; CODATA data]}-
{{СИ јединице}}
{{Authority control}}
[[Категорија:СИ изведене јединице]]
| |||