[tex]B_1=\frac{\mu I_1}{2R}\\ B_2=\frac{\mu I_2}{2\pi r}=\frac{2\mu I_1}{2\pi\frac{R}{3} }=\frac{3\mu I_1}{\pi R}\\ \frac{B_1}{B_2}=\frac{\frac{\mu I_1}{2R}}{\frac{3\mu I_1}{\pi R}}= \frac{\mu I_1*\pi R}{2R*3\mu I_1}=\frac{\pi}{6}=> \frac{B_1}{B_2}=\frac{\pi}{6}[/tex]
