Symbols:Greek/Sigma

Surface Charge Density

 * $$\sigma$$

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

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

The LaTeX code for $$\sigma$$ is \sigma.

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:
 * $$\sigma = \frac m A$$

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

The LaTeX code for $$\sigma$$ is \sigma.