Physics · Ch 10 — Electrostatics
(b) Surface Charge Density
(b) Surface Charge Density
When a total charge q is distributed UNIFORMLY over a surface of area A (Fig. 10.23), the SURFACE CHARGE DENSITY is defined as the charge per unit area: Its SI unit is coulomb per square metre (). Typical physical examples of a surface charge distribution include charge spread uniformly across a thin conducting disc, or across a piece of synthetic cloth. …
What this figure shows. A flat, thin surface (drawn as a disc or rectangular sheet) is shown with small '+' (or dot) symbols distributed evenly all across its area, representing a charge q spread continuously and uniformly over the entire surface. A small element of area dA is marked out somewhere on the surface, indicating the small elemental charge used when integrating over a surface charge distribution …