A Bohr hydrogen atom undergoes a transition $n=5\to n=4$ and emits a photon of frequency $\nu$. Frequency of circular motion of an electron in $n=4$ orbit is ${\nu }_4$. The ratio $\frac{\nu }{{\nu }_4}$ is

• Correct answer
  A

  $\frac{18}{25}$
• B

  $\frac{16}{25}$
• C

  $\frac{9}{25}$
• D

  $\frac{8}{25}$

Hence, the correct answer is option: 'A'.