Current density

From Freepedia

In electricity and magnetism, current density is a measure of the density of electrical current. In a conductor, it is defined as the ratio of current to cross-sectional area of the conductor:

<math> \bold{J} = \frac{I}{A} \bold{\hat{u}}</math>

where û is the unit vector pointing in the direction of the current flow along the length of the conductor.