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| | Hello, I'm Crystal, a 25 year old from Barendrecht, Netherlands.<br>My hobbies include (but are not limited to) Photography, College football and watching Sons of Anarchy.<br><br>Feel free to surf to my website :: [http://crazyuhak.com/xe/index.php?document_srl=180838&mid=info_ph Fifa 15 Coin Generator] |
| {{Infobox Unit
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| | bgcolour =
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| | name = Coulomb
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| | image =
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| | caption =
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| | standard = [[SI derived unit]]
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| | quantity = [[Electric charge]]
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| | symbol = C
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| | dimension = T⋅I
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| | namedafter = [[Charles-Augustin de Coulomb]]
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| | units1 = [[SI base unit]]s
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| | inunits1 = 1 [[Ampere|A]] [[second|s]]
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| | units2 = [[CGS unit]]s
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| | inunits2 = {{gaps|2|997|924|580}} [[statcoulomb|statC]]
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| | units3 = [[Atomic units]]
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| | inunits3 = {{gaps|6.241|509|65|(16)|e=18|[[elementary charge|e]]}}<ref name=CODATA />
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| }}
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| The '''coulomb''' (named after [[Charles-Augustin de Coulomb]], unit symbol: '''C''') is a fundamental unit of electrical charge, and is also the [[SI]] derived unit of [[electric charge]] (symbol: '''Q''' or '''q'''). It is equal to the charge of approximately 6.241{{e|18}} [[electron]]s.
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| Its SI definition is the charge transported by a constant current of one [[ampere]] in one [[second]]:
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| :<math>1\ \mathrm{C} = 1\ \mathrm{A} \times 1\ \mathrm{s}</math>
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| One coulomb is also the amount of excess charge on the positive side of a capacitor of one [[farad]] charged to a potential difference of one [[volt]]:
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| :<math>1\ \mathrm{C} = 1\ \mathrm{F} \times 1\ \mathrm{V}</math>
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| == Name and notation ==
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| {{SI unit lowercase|Charles-Augustin de Coulomb|coulomb|C}}<ref>{{cite web |url=http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf |publisher=BIPM |title=SI Brochure, Appendix 1, |page=144 }}</ref>
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| == Definition ==
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| In the [[SI system]], the coulomb is defined in terms of the [[ampere]] and [[second]]: 1 C = 1 A × 1 s.<ref>{{cite web |url=http://www.bipm.org/en/si/si_brochure/chapter2/2-2/table3.html |publisher=BIPM |title=SI brochure, section 2.2.2 }}</ref> The second is defined in terms of a frequency which is naturally emitted by [[caesium]] atoms.<ref>{{cite web |url=http://www.bipm.org/en/si/si_brochure/chapter2/2-1/second.html |publisher=BIPM |title=SI brochure, section 2.2.1.3 }}</ref> The ampere is defined using [[Ampère's force law]];<ref name=ampere>{{cite web |url=http://www.bipm.org/en/si/si_brochure/chapter2/2-1/ampere.html |publisher=BIPM |title=SI brochure, section 2.2.1.4 }}</ref> the definition relies in part on the mass of the [[Kilogram|international prototype kilogram]], a metal cylinder housed in France.<ref name=wattbalance>{{cite web |url=http://www.bipm.org/en/scientific/elec/watt_balance/ |publisher=BIPM |title=Watt Balance}}</ref> In practice, the [[watt balance]] is used to measure amperes with the highest possible accuracy.<ref name=wattbalance />
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| Since the charge of one electron is known to be about {{gaps|1.602|176|57|e=−19|u=coulombs}}, a coulomb can also be considered to be the charge of roughly {{gaps|6.241|509|324|e=18|u=electrons}} (or protons), the reciprocal of {{gaps|1.602|176|57|e=−19}}.
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| == SI prefixes ==
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| {{SI multiples
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| | unit=coulomb
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| | symbol=C
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| | note=Common multiples are in bold face.
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| | mc=|m=|n=|p=
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| }}
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| See also [[SI prefix#List of SI prefixes|SI prefix]].
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| == Conversions ==
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| * The magnitude of the electrical charge of one [[mole (unit)|mole]] of [[elementary charge]]s (approximately 6.022{{e|23}}, or [[Avogadro's number]]) is known as a [[Faraday constant|faraday unit of charge]] (closely related to the [[Faraday constant]]). One faraday equals {{gaps|96|485.3399|u=coulombs}}. In terms of Avogadro's number (''N''<sub>A</sub>), one coulomb is equal to approximately 1.036 × ''N''<sub>A</sub>{{e|−5}} elementary charges.
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| * One [[ampere-hour]] = 3600 C, 1 mA⋅h = 3.6 C.
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| * The [[elementary charge]] is {{gaps|1.602|176|487|e=−19|u=C}}.<ref name=CODATA />
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| * One [[statcoulomb]] (statC), the obsolete [[CGS]] electrostatic unit of charge (esu), is approximately 3.3356{{e|-10}} C or about one-third of a nanocoulomb.
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| * One coulomb is the magnitude ([[absolute value]]) of electrical charge in {{gaps|6.241|509|65|(16)|e=18}} [[proton]]s or [[electron]]s.<ref name=CODATA />
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| == Relation to elementary charge ==
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| The [[elementary charge]], the charge of a proton (equivalently, the negative of the charge of an electron), is approximately {{gaps|1.602|176|487|(40)|e=-19|u=C}}.<ref name=CODATA>{{CODATA2006 |url=http://physics.nist.gov/cgi-bin/cuu/Value?e}} The inverse value (the number of elementary charges in 1 C) is given by 1/[{{gaps|1.602|176|487|(40)|e=-19}}] = {{gaps|6.241|509|65|(16)|e=18}}.</ref> In SI, the elementary charge in coulombs is an approximate value: no experiment can be infinitely accurate. However, in other unit systems, the elementary charge has an ''exact'' value by definition, and other charges are ultimately measured relative to the elementary charge.<ref name=mills>{{cite doi|10.1088/0026-1394/42/2/001}}</ref> For example, in [[conventional electrical units]], the values of the [[Josephson constant]] ''K<sub>J</sub>'' and [[von Klitzing constant]] ''R<sub>K</sub>'' are exact defined values (written ''K<sub>J-90</sub>'' and ''R<sub>K-90</sub>''), and it follows that the elementary charge ''e'' =2/(''K<sub>J</sub>R<sub>K</sub>'') is also an exact defined value in this unit system.<ref name=mills/> Specifically, ''e''<sub>90</sub> = (2{{e|−9}})/({{gaps|25|812.807}} × {{gaps|483|597.9}}) C exactly.<ref name=mills/> SI itself may someday change its definitions in a similar way.<ref name=mills/> For example, one possible proposed redefinition is "the ampere...is [defined] such that the value of the elementary charge ''e'' (charge on a proton) is exactly {{gaps|1.602|176|487|e=−19}} coulombs"<ref>[http://www.bipm.org/utils/en/ppt/23report_ccu.ppt Report of the CCU to the 23rd CGPM]</ref> This proposal is not yet accepted as part of the SI; the SI definitions are unlikely to change until at least 2015.<ref>{{cite web
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| |url = http://www.bipm.org/utils/en/pdf/BIPM_Bulletin.pdf
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| |title = BIPM Bulletin
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| |author = Anon
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| |publisher = BIPM
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| |date = November 2010
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| |accessdate = 2011-01-28}}</ref>
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| == In everyday terms ==
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| *The charges in [[static electricity]] from rubbing materials together are typically a few microcoulombs.<ref>{{cite web |url=http://www-zeuthen.desy.de/~pohlmadq/teach/112/ch16.pdf |publisher=[[DESY]] |title=Physics: Principles with Applications |author=Martin Karl W. Pohl}}</ref>
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| *The amount of charge that travels through a [[lightning|lightning bolt]] is typically around 15 C, although large bolts can be up to 350 C.<ref>Hasbrouck, Richard. [https://www.llnl.gov/str/pdfs/05_96.1.pdf Mitigating Lightning Hazards], Science & Technology Review May 1996. Retrieved on 2009-04-26.</ref>
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| *The amount of charge that travels through a typical [[Alkaline battery|alkaline]] [[AA battery]] is about 5 kC = 5000 C ≈ 1.4 [[Ampere-hour|A⋅h]]. After that charge has flowed, the battery must be discarded or recharged.<ref>{{Google books|eftR-e1nVAgC|How to do everything with digital photography – David Huss|page=23}}, "The capacity range of an AA battery is typically from 1100–2200 mAh."</ref>
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| *According to [[Coulomb's law]], two negative [[point charge]]s of {{val|+1|u=C}}, placed one meter apart, would experience a repulsive [[force]] of {{val|9|e=9|u=N}}, a force roughly equal to the weight of {{gaps|920|000}} metric tons of [[mass]] on the surface of the Earth.
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| *The [[hydraulic analogy]] uses everyday terms to illustrate movement of charge and the transfer of energy. The analogy equates charge to a volume of water, and voltage to pressure. One coulomb equals (the negative of) the charge of {{val|6.24|e=18|u=electrons}}. The amount of energy transferred by the flow of 1 Coulomb can vary; for example, 300 times fewer electrons flow through a lightning bolt than through an AA battery, but the total energy transferred by the flow of the lightning's electrons is 300 million times greater.
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| == See also ==
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| * [[Abcoulomb]], a cgs unit of charge
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| * [[Ampère's circuital law]]
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| * [[Coulomb's law]]
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| * [[Electrostatics]]
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| * [[Elementary charge]]
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| * [[Faraday (unit)]], an obsolete unit
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| * [[Quantity of electricity]]
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| == Notes and references ==
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| {{Reflist|2}}
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| {{SI units}}
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| [[Category:SI derived units]]
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| [[Category:Units of electrical charge]]
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Hello, I'm Crystal, a 25 year old from Barendrecht, Netherlands.
My hobbies include (but are not limited to) Photography, College football and watching Sons of Anarchy.
Feel free to surf to my website :: Fifa 15 Coin Generator