Question

The ratio of the wavelengths for $2\to 1$ transition in $L{i}^{++},H{e}^{+}$ and H is

• A. 1 : 2 : 3
• B. 1 : 4 : 9
• C. 4 : 9 : 36
• D. 3 : 2 : 1

Answer 1

The correct option is C 4 : 9 : 36

Using $\frac{1}{\lambda }=R{Z}^2(\frac{1}{n_1^2}-\frac{1}{n_2^2})\Rightarrow \lambda \alpha \frac{1}{Z^2}\Rightarrow {\lambda }_{Li}:{\lambda }_{H{e}^{+}}:{\lambda }_H=\frac{1}{9}:\frac{1}{4}:\frac{1}{1}=4:9:36$