Question

What is the maximum wavelength line in the Lyman series of $H{e}^{+}$ion?

• A. $3R$
• B. $\frac{1}{3R}$
• C. $\frac{1}{R}$
• D. None of these

Answer 1

Answer: (B)

$\frac{1}{\lambda }=R{Z}^2\left[\frac{1}{n_1^2}-\frac{1}{n_2^2}\right]$
$=R\times 2^2\left[\frac{1}{1^2}-\frac{1}{2^2}\right]$
$\Rightarrow 3R;\lambda =\frac{1}{3R}$