# Optics

Classified in Physics

Written at on English with a size of 4.1 KB.

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**charge conservation**is the principle that the total

**electric charge**in an

**isolated system**never changes.

^{[1]}The net quantity of electric

**charge**, the amount of

**positive charge**minus the amount of

**negative charge**in the universe, is always

*. Charge conservation, considered as a*

**conserved****physical conservation law**, implies that the change in the amount of

**electric charge**in any volume of space is exactly equal to the amount of charge flowing into the volume minus the amount of charge flowing out of the volume. In essence,

**charge conservation**is an accounting relationship between the amount of charge in a region and the flow of charge into and out of that region, given by a

**continuity equation**between

**charge density**{\displaystyle \rho (\mathbf {x} )} and

**current density**{\displaystyle \mathbf {J} (\mathbf {x} )}.