Symbols:Greek/Sigma

Event Space

 * $\Sigma$

Sigma Function

 * $\sigma \left({n}\right)$

Surface Charge Density

 * $\sigma$

Used to denote the surface charge density of a given body:
 * $\displaystyle \sigma = \frac q A$

where:
 * $q$ is the body's electric charge;
 * $A$ is the body's area.

Area Density

 * $\sigma$

Used sometimes, although $\rho_A$ (Greek letter rho) is more common, to denote the area density of a given two-dimensional body:
 * $\sigma = \dfrac m A$

where:
 * $m$ is the body's mass;
 * $A$ is the body's area.