# Simple Maxwell Equation question

1. May 13, 2013

### ZedCar

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

In the Maxwell eqn

divD = ρ (sub f)

What does ρ sub f represent?

2. Relevant equations

3. The attempt at a solution

Does is represent volume density of charge?

2. May 13, 2013

### HallsofIvy

No, B is the magnetic field flux so $\rho_f$ is the "volume density of magnetism". Since there are no "magnetic monopoles", that should always be 0.

3. May 13, 2013

### ZedCar

Thanks very much HallsofIvy!

4. May 13, 2013

### ehild

D is the vector of electric displacement and its divergence is equal to the volume charge density. "f" can mean "free", the excess macroscopic charge density.
http://scienceworld.wolfram.com/physics/D.html

ehild

5. May 13, 2013

### ehild

HallsofIvy, the question was "D" not "B".

ehild