For wavelength of visible radiation of hydrogen spectrum Balmer gave an equation as…
For wavelength of visible radiation of hydrogen spectrum Balmer gave an equation as $\lambda=\frac{\left(\mathrm{km}^2\right)}{\left(\mathrm{m}^2-4\right)}$, where $m$ is the integer value. The value of $k$ in terms of Rydberg's constant $R$ is
$\frac{R}{4}$
$\frac{4}{R}$
$R$
$4 R$
Solution
Wavelength of visible radiation in Balmer series is given by,
$\begin{aligned} & \frac{1}{\lambda}=R\left(\frac{1}{4}-\frac{1}{m^2}\right) \text { for } m \geq 2 \\ & \Rightarrow \lambda=\frac{4}{R} \cdot \frac{m^2}{m^2-4}=\frac{k m^2}{m^2-4}\end{aligned}$
$\therefore k=\frac{4}{R}$