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A Greek sigma, the reciprocal of resistivity.
Also known as: Electrical conductivity, Specific conductance, Sigma in physics
Conductivity says how readily a material carries current, and it is exactly one over the resistivity — which is written with the Greek rho. That two reciprocal quantities have two symbols is a convenience; that σ also means stress, surface charge and standard deviation is not.
Denotes electrical conductivity, the reciprocal of resistivity, in siemens per metre.
Contexts: Laboratory
Is a material property independent of shape, unlike conductance, which depends on the specimen's dimensions.
Contexts: Laboratory
Collides with mechanical stress, surface charge density, the Stefan–Boltzmann constant and the standard deviation.
Contexts: Laboratory
A Greek lowercase sigma, a small loop with a horizontal stroke leading right from its top.