Gauss (unit)

Unit of magnetic induction

The gauss (symbol: G, sometimes Gs), is a unit of measurement of magnetic induction, also known as magnetic flux density. The unit is part of the Gaussian system of units, which inherited it from the older centimetre–gram–second electromagnetic units (CGS-EMU) system. It was named after the German mathematician and physicist Carl Friedrich Gauss in 1936. One gauss is defined as one maxwell per square centimetre.

As the centimetre–gram–second system of units (cgs system) has been superseded by the International System of Units (SI), the use of the gauss has been deprecated by the standards bodies, but is still regularly used in various subfields of science. The SI unit for magnetic flux density is the tesla (symbol T),[1] which corresponds to 10,000gauss.

Name, symbol, and metric prefixes

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Albeit not a component of the International System of Units, the usage of the gauss generally follows the rules for SI units. Since the name is derived from a person's name, its symbol is the uppercase letter G. When the unit is spelled out, it is written in lowercase ("gauss"), unless it begins a sentence.[2]: 147–148  The gauss may be combined with metric prefixes,[3]: 128  such as in milligauss, mG (or mGs), or kilogauss, kG or kGs.

Unit conversions

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1 G = M x ⋅ c m − 2 = g B i ⋅ s 2  ≘  10 − 4 T = 10 − 4 k g A ⋅ s 2 {\displaystyle {\begin{aligned}1\,{\rm {G}}&={\rm {Mx}}{\cdot }{\rm {cm}}^{-2}={\frac {\rm {g}}{{\rm {Bi}}{\cdot }{\rm {s}}^{2}}}\\&{\text{ ≘ }}10^{-4}\,{\rm {T}}=10^{-4}{\frac {\rm {kg}}{{\rm {A}}{\cdot }{\rm {s^{2}}}}}\end{aligned}}}

The gauss is the unit of magnetic flux density B in the system of Gaussian units and is equal to Mx/cm2 or g/Bi/s2, while the oersted is the unit of H-field. One tesla (T) corresponds to 104 gauss, and one ampere (A) per metre corresponds to 4π × 10−3 oersted.

The units for magnetic flux Φ, which is the integral of magnetic B-field over an area, are the weber (Wb) in the SI and the maxwell (Mx) in the CGS-Gaussian system. The conversion factor is 108 maxwell per weber, since flux is the integral of field over an area, area having the units of the square of distance, thus 104 G/T (magnetic field conversion factor) times the square of 102 cm/m (linear distance conversion factor). 108 Mx/Wb = 104 G/T × (102 cm/m)2.

Typical values

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See also

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Notes

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1. ^

   The electromagnetic Gaussian and SI quantities correspond (symbol '≘') rather than being equal (symbol '=').

2. ^

   c

   cgs =
   2.997

   924

   58

   ×

   1010
   is the numeric part of the

   is the numeric part of the speed of light when expressed in cgs units.

References

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