Time taken for an electron to complete one revolution in the Bohr orbit of hydrogen atom is

The time taken by an electron to complete one revolution of Bohr's orbit of the hydrogen atom(t) =$\frac{\mathrm{distance}}{\mathrm{velocity}}$

Bohr's orbit is circular. So, the distance =2πr.    .....(i)

Where r is the radius of the Bohr's orbit.

$$\begin{gathered} \mathrm{we} \mathrm{know} \mathrm{that}, \mathrm{mvr}=\frac{\mathrm{nh}}{2\mathrm{\pi }} \\ \mathrm{v}=\frac{\mathrm{nh}}{2\mathrm{\pi mr}}---\left(2\right) \\ \mathrm{t}=\frac{2\mathrm{\pi r}}{\left(\frac{\mathrm{nh}}{2\mathrm{\pi mr}}\right)}=\frac{4{\mathrm{\pi }}^2{\mathrm{mr}}^2}{\mathrm{nh}} \end{gathered}$$