Physics - Modern Physics Question with Solution | TestHub

For Brackett series, $n_1=4,n_2=5,6,7\dots \dots \dots$ $\frac{1}{\lambda }=R\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$ where $R=1.09678\times 10^7{\mathrm{m}}^{-1}$, called Rydberg's constant. $$\frac{1}{\lambda }=R\left(\frac{1}{4^2}-\frac{1}{n_2^2}\right)$$ For maximum wavelength, $n_2=5$ $$\begin{array}{rl}& \frac{1}{{\lambda }_{\max }}=1.09687\times 10^7\left(\frac{1}{4^2}-\frac{1}{5^2}\right)\\ & {\lambda }_{\max }=40519\mathring{A}\end{array}$$