Q 12-12-024NEETJEE MainMedium
The frequency of revolution of the electron in the $n^{\text{th}}$ Bohr orbit varies with $n$ as
Answer: (A) $\dfrac{1}{n^3}$
Concept. The frequency of revolution is $f = \dfrac{v}{2\pi r}$, with $v \propto \dfrac{1}{n}$ and $r \propto n^2$ in the Bohr model.
Step 1. Combine.
$$f \propto \frac{1/n}{n^2} = \frac{1}{n^3}$$
Answer. $\dfrac{1}{n^3}$ (Option A).
Solution by Sreeraj P, M.Sc Physics