\(m v r=\frac{n h}{2 \pi} \rightarrow m \omega r^2=\frac{n h}{2 \pi} \rightarrow \omega \propto \frac{1}{n^3}\)

\(I=q_e \frac{1}{2 \pi} \quad \text { as } r \propto n^2\)

\(B=\mu_0 \frac{1}{2 r}\)

\(B=\frac{\mu_0}{2 \pi} \frac{\omega}{2 r} \text { again as } r \propto n^2\)

\(\therefore B \propto \frac{1}{n^5}\)