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{{Warning|If hard core The [https://en.wikipedia.org/wiki/International_System_of_Units SI or International System of Units] versus the [https://en.wikipedia.org/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units CGS or Centimetre–gram–second] system of units is a constant source of confusion in the field of NMR. Both are based on the metric system, however the differences can result in quite different forms of the fundamental NMR or physics theory equations. An example of this is Tesla versus Gauss units for the magnetic field strength. == CGS flavours == Note that in the CGS system, that there are different sets of units for electromagnetism. The major systems are [https://en.wikipedia.org/wiki/Centimetre_gram_second_system_of_units#Electrostatic_units_.28ESU.29 ESU], [https://en.wikipedia.org/wiki/Centimetre_gram_second_system_of_units#Electromagnetic_units_.28EMU.29 EMU], [https://en.wikipedia.org/wiki/Gaussian_units Gaussian units], and [https://en.wikipedia.org/wiki/Lorentz%E2%80%93Heaviside_units Lorentz-Heaviside units]. In NMR papers not using SI units, the EMU system is most commonly used. == Units of measurement == {|class="wikitable" style="text-align:center;"|-! Quantity ! Symbol! colspan="3" | SI unit! colspan="3" | CGS unit (EMU)! SI to your taste, please do not read any furtherCGS conversion factor|-!!! Name! Symbol! [https://en.wikipedia.org/wiki/SI_base_unit Base units]! Name! Symbol! Base units!|-! length || ''L''|style="text-align:left;"| metre|| m|| m|style="text-align:left;"| centimetre|| cm|| cm|| 10<sup>−2</sup>|-! mass|| ''m''|style="text-align:left;"| kilogram|| kg|| kg|style="text-align:left;"| gram|| g|| g|| 10<sup>−3</sup>|-! time || ''t''|style="text-align:left;"| second|| s|| s|style="text-align:left;"| second|| s|| s|| 1|-! velocity || ''v''|style="text-align:left;"| metre per second|| || m⋅s<sup>−1</sup>|style="text-align:left;"| centimetre per second|| || cm⋅s<sup>−1</sup>|| 10<sup>−2</sup>|-! acceleration || ''a''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Metre_per_second_squared metre per second squared]|| || m⋅s<sup>−2</sup>|style="text-align:left;"| [https://en.wikipedia.org/wiki/Gal_%28unit%29 galileo]|| Gal|| cm⋅s<sup>−2</sup>|| 10<sup>−2</sup>|-! force|| ''F''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Newton_%28unit%29 Newton]|| N|| kg⋅m⋅s<sup>−2</sup>|style="text-align:left;"| [https://en.wikipedia.org/wiki/Dyne dyne]|| dyn|| g·cm·s<sup>−2</sup>|| 10<sup>−5</sup>|-! energy || ''E''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Joule Joule]|| J|| kg⋅m<sup>2</sup>·s<sup>−2</sup>|style="text-align:left;"| [https://en.wikipedia.org/wiki/Erg erg]|| erg|| g·cm<sup>2</sup>·s<sup>2</sup>|| 10<sup>−7</sup>|-! power|| ''P''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Watt Watt]|| W|| kg⋅m<sup>2</sup>·s<sup>−3</sup>|style="text-align:left;"| erg per second|||| g·cm<sup>2</sup>·s<sup>−3</sup>|| 10<sup>−7</sup>|-! magnetic dipole moment|| ''μ''|style="text-align:left;"| Newton-meters per Tesla|||| A·m<sup>2</sup>|style="text-align:left;"| electromagnetic unit|| emu|| abA·cm<sup>2</sup>|| 10<sup>−3</sup>|-! magnetic flux density (B-field)|| ''B''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Tesla_%28unit%29 Tesla]|| T|| kg·s<sup>−2</sup>·A<sup>−1</sup>|style="text-align:left;"| [https://en.wikipedia.org/wiki/Gauss_%28unit%29 Gauss]|| Gs|| Mx·cm<sup>−2</sup>|| 10<sup>−4</sup>|-! magnetic flux density (H-field)|| ''H''|style="text-align:left;"| Amperes per metre|| || A·m<sup>−1</sup>|style="text-align:left;"| [https://en.wikipedia.org/wiki/Oersted Oersted]|| Oe|| g·cm·s<sup>−2</sup>|| 4π·10<sup>−3</sup>|-! magnetic flux|| ''Φ<sub>B</sub>''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Weber_%28unit%29 Weber]|| Wb|| kg·m<sup>2</sup>·s<sup>−2</sup>·A<sup>−1</sup>|style="text-align:left;"| [https://en.wikipedia.org/wiki/Maxwell_%28unit%29 Maxwell]|| Mx|| Mx|| 10<sup>−8</sup>|-! magnetic susceptibility|| ''χ<sub>m</sub>''|style="text-align:left;"||| || -|style="text-align:left;"||| || -|| (4π)<sup>−1</sup>|-! electric current|| ''I''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Ampere ampere]|| A|| A|style="text-align:left;"| [https://en.wikipedia.org/wiki/Abampere abampere] (or biot)|| abA (or Bi)|| abA (or Bi)|| 10<sup>−1</sup>|-!}electric charge|| ''Q''|style="text-align:left;"| [https://en.wikipedia.org/wiki/Coulomb coulomb]|| C|| A·s|style="text-align:left;"| [https://en.wikipedia.org/wiki/Abcoulomb abcoulomb]|| abC|| abA·s|| 10<sup>−1</sup>|}
The == Constants == {|class="wikitable" style="text-align:center;"|-! Constant ! Symbol! colspan="3" | SI unit! colspan="3" | CGS unit (EMU)! SI to CGS conversion factor|-!!! Definition! Value! [https://en.wikipedia.org/wiki/International_System_of_Units SI or International System of UnitsSI_base_unit Base units] versus the [https:! Definition! Value! Base units!|-! magnetic force constant|| ''k''<sub>A</sub>|| ''µ<sub>0</sub>''·(4π)<sup>−1</sup>|| 10<sup>−7</sup>|| kg⋅m·s<sup>−2</sup>·A<sup>−2</sup>|| Unity|| 1|| || 4π·''µ<sub>0</sub>''<sup>−1</sup>|-! magnetic constant|| ''µ<sub>0</sub>''|| ''µ<sub>0</sub>''|| 4π·10<sup>−7</sup>|| kg·m·s<sup>−2</sup>·A<sup>−2</en.wikipedia.orgsup>|| Unity|| 1|| || ''µ<sub>0</wikisub>''<sup>−1</Centimetre%E2%80%93gram%E2%80%93second_system_of_units CGS or Centimetre–gram–secondsup>|} == See also == [[Category:Theory]] system of units is a constant source of confusion in the field of NMR. Both are based on the metric system, however the differences can result in quite different forms of the fundamental NMR equations. An example of this is Tesla versus Gauss units for the magnetic field strength.
Added Category:Theory.
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