Question

Ratio of the wavelengths of first line of Lyman series and first line of Balmer series is

• A. 1 : 3
• B. 27 : 5
• C. 5 : 27
• D. 4 : 9

Answer 1

The correct option is C 5 : 27

For Lyman series $\frac{1}{{\lambda }_{L_1}}=R[\frac{1}{1^2}-\frac{1}{2^2}]=\frac{3R}{4}$ ....... (i)
For Balmer series $\frac{1}{{\lambda }_{B_1}}=R[\frac{1}{2^2}-\frac{1}{3^2}]=\frac{5R}{36}$ ....... (ii)
From equation (i) and (ii) $\frac{{\lambda }_{L_1}}{{\lambda }_{B_1}}=\frac{5}{27}$