Two concentric circular coils, one of small radius r 1 and the...

Options

1. A$\frac{{{\mu }_{0}}\pi {{r}_{1}}}{{{r}_{2}}}$
2. B$\frac{{{\mu }_{0}}\pi {{r}_{2}}}{2{{r}_{1}}}$
3. C$\frac{{{\mu }_{0}}\pi {{r}_{2}}}{{{r}_{1}}}$
4. D$\frac{{{\mu }_{0}}\pi {{r}_{1}}}{2{{r}_{2}}}$