# Gauss (unit)

Physical unit
Unit name Gauss
Unit symbol ${\ displaystyle \ mathrm {Gs, \, G}}$
Physical quantity (s) Magnetic flux density
dimension ${\ displaystyle {\ mathsf {M ^ {1/2} L ^ {- 1/2} T ^ {- 1}}}}$
system Electromagnetic CGS unit system , Gaussian CGS unit system
In SI units ${\ displaystyle \ mathrm {1 \, Gs \ sim 10 ^ {- 4} \; {\ frac {kg} {A \, s ^ ​​{2}}} = 0 {,} 1 \; mT}}$
In CGS units ${\ displaystyle \ mathrm {1 \, Gs = 1 \; {\ sqrt {\ frac {erg} {cm ^ {3}}}} = 1 \; {\ sqrt {\ frac {g} {cm \ cdot s ^ {2}}}}}}$
Named after Carl Friedrich Gauss

Gauss (in Switzerland or under English-speaking influence also Gauss ; unit symbols : Gs , G ; after Carl Friedrich Gauß ) is the unit of the magnetic flux density  B in the electromagnetic CGS system and in the Gaussian CGS system :

${\ displaystyle \ mathrm {1 \ Gs = 1 \ {\ frac {\ sqrt {g}} {{\ sqrt {cm}} \ cdot s}}}}$

In Germany, the Gauss has not been a legal unit in metrology since 1970 , but is still used , especially in astrophysics . Instead, the legal unit of magnetic flux density in the EU and Switzerland is Tesla , the corresponding unit in the International System of Units  (SI):

{\ displaystyle {\ begin {aligned} \ mathrm {1 \ Gs} & \ {\ mathrel {\ hat {=}}} \ \ mathrm {0 {,} 1 \ mT = 100 \ \ mu \ mathrm {T} = 10 ^ {- 4} \ T} \\\ Leftrightarrow \ mathrm {10 ^ {4} \ Gs} = \ mathrm {10,000 \ Gs} & \ {\ mathrel {\ hat {=}}} \ \ mathrm { 1 \ T} \ end {aligned}}}

## Conversions

In parallel with Gauss, the unit gamma existed for the magnetic flux density :

{\ displaystyle {\ begin {aligned} \ mathrm {1 \ \ gamma} & = \ mathrm {10 ^ {- 5} \ Gs \ {\ mathrel {\ hat {=}}} \ 10 ^ {- 9} \ T} \\\ Leftrightarrow \ mathrm {10 ^ {5} \ \ gamma} = \ mathrm {100,000 \ \ gamma} & = \ mathrm {1 \ Gs} \ end {aligned}}}

The Gauss is often confused with the Gaussian CGS unit of the magnetic field strength  H, the Oersted , which can also be represented as in the Gaussian system of units and in electromagnetic CGS systems . The reason for this formal equality is that magnetic flux density and magnetic field strength in the above-mentioned unit systems are of the same dimension (unlike in the SI, where the two quantities always differ by the magnetic permeability or the magnetic field constant as a proportionality factor ). ${\ displaystyle \ mathrm {\ frac {\ sqrt {g}} {{\ sqrt {cm}} \ cdot s}}}$ ${\ displaystyle \ mu}$ ${\ displaystyle \ mu _ {0}}$

## Historical

"Gauss" as the name of the electromagnetic CGS unit for the magnetic field strength was specified in 1900 at the 5th  International Electricity Congress in Paris. As a result of a misunderstanding, the American delegates assumed that “Gauss” had been agreed as the name for the electromagnetic CGS unit of magnetic flux density . This ambiguity was cleared up in favor of the American view at the IEC meeting in Stockholm and Oslo in 1930 .

In 1933, at a meeting in Paris, the IEC stipulated that 1 cm −1/2 g 1/2 s −1 as the electromagnetic CGS unit of the magnetic field strength should be called Oersted.

The unit symbol "Gs" for Gauss was established by the IEC in 1935 at a conference in Scheveningen .

## literature

1. ^ Ulrich Stille: Measuring and calculating in physics . 2nd Edition. Vieweg, Braunschweig 1961, p. 212 .