\({\mathrm{N}} \mu_{0} \mathrm{n} \mathrm{I} \pi \mathrm{R}^{2}=\mathrm{LI}\)
\(\mathrm{N} \mu_{0} \frac{\mathrm{N}}{\ell} \mathrm{I} \pi \mathrm{R}^{2}=\mathrm{LI}\)
\(\mathrm{N}\) and \(\mathrm{R}\) constant
Self inductance \((L)\) \(\propto \frac{1}{\ell} \propto \frac{1}{\text { length }}\)