A particular hydrogen- like ion emits the radiation of frequency 3 × 10^15 Hz when it makes transition from n =2 to n =1. The frequency of radiation…

A particular hydrogen- like ion emits the radiation of frequency $\displaystyle 3 \times 10^{15} \mathrm{~Hz}$ when it makes transition from $\displaystyle \mathrm{n}=2$ to $\displaystyle \mathrm{n}=1$. The frequency of radiation emitted in transition from $\displaystyle \mathrm{n}=3$ to $\displaystyle \mathrm{n}=1$ is $\displaystyle \frac{x}{9} \times 10^{15} \mathrm{~Hz}$, when $\displaystyle x=$ $\displaystyle \_\_\_\_$.