Statvolt: Difference between revisions

Note: the reason why [[Template:Infobox unit|Infobox unit]] is not used is that conversions between CGS-ESU, CGS-EMU, and SI units for electromagnetic quantities have to use the expression 'corresponds to' rather than 'equals', as in '1 abCoulomb corresponds to 2.99 × 10^10 statCoulombs'. The symbol for that is '≘' or '≙'. See e.g. https://arxiv.org/abs/1506.01951, pp. 57–59.

| label2 = [[System of measurement|Unit system]] | data2 = [[Centimetre–gram–second_system_of_units#Electrostatic_units_(ESU)|CGS-ESU]] and [[Gaussian units|CGS-Gaussian]]

| label5 = Named after | data5 = [[Alessandro Volta]]

| label6 = In CGS base units | data6 = g{{sup|1/2}}·cm{{sup|1/2}}/s {{refn|name="Gyllenbok 2018"|

{{cite book

|last1=Gyllenbok |first1=Jan

|title=Encyclopaedia of Historical Metrology, Weights, and Measures: Volume 1

|date=2018

|publisher=Birkhäuser |isbn=978-3-319-57598-8 |language=en

}}}}^{:[https://books.google.com/books?id=XnRVDwAAQBAJ&dq=%22Encyclopaedia%20of%20Historical%20Metrology%2C%20Weights%2C%20and%20Measures%22%20vol%201&pg=PA26 26]}

| data8 = <tr class="nowrap"><td>{{val|1|u=statV}} ''in ...''</td><td>''... corresponds to ...''</td></tr>

| label9 = [[SI]] | data9 = {{math|''c''}}{{sub|cgs}}&nbsp;{{val|e=-8|ul=volt}}<br>= {{val|299.792458|u=volt}}{{efn|name="cCGC"|The dimensionless constant {{math|''c''}}{{sub|cgs}} {{=}} {{val|2.99792458e10}} is numerically equal to the magnitude of the [[speed of light]] when the latter is expressed in {{val|u=cm/s}}.}}

| label10 = [[Centimetre–gram–second_system_of_units#Electrostatic_units_(ESU)|CGS-EMU]]

| data10 = {{math|''c''}}{{sub|cgs}}&nbsp;[[abvolt]]

The '''statvolt''' is a unit of [[voltage]] and [[electrical potential]] used in the [[Centimetre–gram–second_system_of_units#Electrostatic_units_(ESU)|CGS-ESU]] and [[Gaussian units|gaussian]] systems of units. In terms of its relation to the [[SI]] units, one statvolt corresponds to {{math|''c''}}{{sub|cgs}}&nbsp;{{val|e=-8|ul=volt}},{{efn|name="cCGC"}} i.e. to 299.792458&nbsp;[[volt]]s.{{refn|name="Purcell"|{{cite book|last=Purcell|first=Edward|title=Electricity and Magnetism|url=https://archive.org/details/electricitymagne00purc_621|url-access=limited|year=2011|publisher=Cambridge University Press|location=Cambridge|isbn=9781107013605|pages=[https://archive.org/details/electricitymagne00purc_621/page/n493 474]–475|edition=Second}}}}{{efn|As of the [[2019 redefinition of the SI base units]], this correspondence is not longer exact.}}

The statvolt is also defined in the [[CGS]] system as 1&nbsp;[[erg]] / [[statcoulomb]].{{refn|name="Purcell"}}

It is a useful unit for [[electromagnetism]] because, in a vacuum, an [[electric field]] of one statvolt per centimetre has the same energy density as a [[magnetic field]] of one [[Gauss (unit)|gauss]]. Likewise, a plane wave propagating in a vacuum has perpendicular electric and magnetic fields such that for every gauss of magnetic field intensity there is one statvolt/cm of electric field intensity.{{refn|name="Purcell"}}

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== References ==

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