Question

In the spectrum of hydrogen atom, ratio of the longest wavelength in Lyman series to the longest wavelength in Balmer series is:

• A. $\frac{5}{27}$
• B. $\frac{1}{93}$
• C. $\frac{4}{9}$
• D. $\frac{3}{2}$

Answer 1

The correct option is A $\frac{5}{27}$

For longest wavelength in Lyman series, ${\lambda }_L=\frac{1}{R(1-\frac{1}{4})}$
For longest wavelength in Balmer series, ${\lambda }_B=\frac{1}{R(\frac{1}{4}-\frac{1}{9})}$
Hence, $\frac{{\lambda }_L}{{\lambda }_B}=\frac{5}{27}$