# Ampere's Law problem help

1. Mar 5, 2005

### robert25pl

Magnetic field due to a solid wire of current using Ampere's circuital law. Current flows with density $$J=J_{o}\frac{U}{r}a_{z}$$ [A/m^2] along long solid cylindrical wire of radius a having the z-axis as its axis. Find H

$$\oint_{c}H\cdot\,dl=\int_{s}J\cdot\,dS$$

Am I on the right way to solution?

$$\int_{s}J\cdot\,dS =$$
$$=\int_{r=0}^{r} \int_{\Phi}^{2\pi}J_{o}\frac{U}{r}a_{z}\cdot\ r \ dr\, d\phi\,a_{z}$$

Thank You very much for any help?

Last edited: Mar 6, 2005
2. Mar 6, 2005

### robert25pl

I just finish this problem. It was not that difficult as I thought at the beginning. Thanks