# Homework Help: Ampère's Law

1. Mar 5, 2007

### Gyroscope

1. The problem statement, all variables and given/known data
Would someone, please, show me that, if there is no current inside, that:

$$\oint \vec B \cdot d\vec l=0$$

2. Relevant equations

3. The attempt at a solution

2. Mar 5, 2007

### marcusl

You can do this yourself! First use Stokes's theorem to relate your integral to a surface integral over curl(B), then substitute Maxwell's eqn. for curl(B). Note what happens if J and dD/dt are zero.

3. Mar 5, 2007

### Gyroscope

I do not know Stokes Theorem. :) I am preparing to IPHO.