
$\int \mathrm{B} \cdot \mathrm{d} \ell=\mu_{0} \mathrm{I}_{\mathrm{m}}$
$\mathrm{B} \cdot 2 \pi \mathrm{r}=\mu_{0} \mathrm{J} \mathrm{zr}^{2}$
$\mathrm{B}_{1}=\frac{\mu_{0} \mathrm{J}_{1}}{2}$
$\mathrm{B}_{2}=\frac{\mu_{0} \mathrm{J} \overrightarrow{\mathrm{r}}_{2}}{2}$
$B_{\text {net }}=\frac{\mu_{0} J\left(\vec{r}_{1}-\vec{r}_{2}\right)}{2}$
$B_{\text {net }}=\frac{\mu_{0} J a}{2}$



