Question

The ratio of wave length of first line of Lyman series to the first line of Balmer series is

• A. 1 : 4
• B. 5 : 27
• C. 27 : 20
• D. 20 : 27

Answer 1

The correct option is B 5 : 27

${\lambda }_1=\frac{4}{3R}$ ${\lambda }_2=\frac{36}{5R}$
$\frac{{\lambda }_1}{{\lambda }_2}=\frac{4}{3}\times \frac{5}{36}=\frac{5}{27}$