Physics - Modern Physics Question with Solution | TestHub

$\frac{1}{\lambda }=R\left[\frac{1}{n_f^2}-\frac{1}{n_i^2}\right]$

Balmer Series;$n_f=2;n_i=\mathrm{3,4},5,......$

$\frac{1}{\lambda }=1.097\times 10^7 \mathrm{m}=\left[\frac{1}{4}-\frac{1}{9}\right]$

$\Rightarrow \frac{1}{\lambda }=1.097\times 10^7 \mathrm{m}=\left[\frac{5}{36}\right]$

$\Rightarrow \lambda =\frac{36}{5}\times \frac{10^{-7}}{1.097} \mathrm{m}$

$\Rightarrow \lambda =6.56\times 10^{-7} \mathrm{m}$

$\Rightarrow \lambda =656\times 10^{-9} \mathrm{m}$

This wavelength falls in visible range.