Gauss (unit)

In physics, gauss (symbol G) is the unit of strength of magnetic flux density |B| (also known as magnetic induction). The gauss belongs to the Gaussian and emu (electromagnetic) systems of units, which are cgs (centimeter-gram-second) systems. The unit is related to the SI unit tesla (T) as follows.

1 G ≡ 1 Mx/cm² = 10⁻⁴  T,

where Mx (maxwell) is the Gaussian unit for magnetic flux.

The unit is named in honor of the German mathematician and physicist Carl Friedrich Gauss.

Definition

The gauss is defined through an electromotive force ${\mathcal {E}}$ induced by a change in magnetic field B. For constant surface S and uniform rate of decrease of |B|, Faraday's law takes the simple form

$|\mathbf {B} |={\frac {\Phi }{S}}=-{\frac {t\,{\mathcal {E}}}{S}},$

where Φ is the magnetic flux passing through S and uniform rate of decrease means linearity in time: $\Phi =-t{\mathcal {E}}.$ Hence, gauss is equal to maxwell per unit surface, where maxwell (symbol Mx) is the Gaussian unit for Φ, and |B| is a flux density.

In Gaussian units S is in cm², time t in s, ${\mathcal {E}}$ in abV ( = 10⁻⁸ volt), |B| in G, and Φ in Mx:

1 G = 1 Mx/cm² = 1 abV•s/cm²

Related unit

• The oersted is the Gaussian unit of strength of a magnetic field |H|. The oersted is defined by means of an electric current giving the field H.