# What is the physical meaning of the continuity equation

1. Jun 1, 2007

### angel 42

1. The problem statement, all variables and given/known data

I'm new here and I would like to ask a simple Q:
what is the physical meaning of the continuity equation
from (electrodynamic 1) I mean it's related to the electromagnatic problems

2. Relevant equations

3. The attempt at a solution
I know the answer in my language it's easy but I like to see it in english

Last edited: Jun 1, 2007
2. Jun 1, 2007

### Dox

Hello.

The continuity equation is,
$$\frac{\partial\rho}{\partial t}+\vec{\nabla}\cdot\vec{j}=0.$$

It means:
If you take a mathematical closed surface in the space (it means that your surface could be not a real one but yous an imaginary boundary), if the number of charge particles inside your boundary change on time, is because the missing ones have crossed.

That is, the change of the charge density on times is equal to the flux of charge through the surface enclosing the volume.

I hope it would be useful to you. Regards.

3. Jun 2, 2007

### angel 42

thanks Dox by the way I do Know the answer but I try to write it in english in my open book exam, and that is close to mine

and this word is to the physics furoms
be ware I'm coming