Q. The ratio of the frequencies of the long wavelength limits of the Lyman and Balmer series of hydrogen is
A) $27:5$
B) $5:27$
C) $4:1$
D) $1:4$
Explanation
(a) $\frac{\lambda_{L}}{\lambda_{B}} = \left( \frac{\frac{1}{2^{2}} - \frac{1}{3^{2}}}{\frac{1}{1^{2}} - \frac{1}{2^{2}}} \right) = \frac{5/36}{3/4} = \frac{5}{27}$
$\frac{v_{L}}{v_{B}} = \frac{27}{5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.