Q. The wavelength of the first line of Balmer series is $6563\ \mathring{\mathrm{A}}$. The Rydberg constant for hydrogen is about
A) $1.09 \times 10^{7}per\ m$
B) $1.09 \times 10^{8}per\ m$
C) $1.09 \times 10^{9}per\ m$
D) $1.09 \times 10^{5}per\ m$
Explanation
(a) $\frac{1}{\lambda} = R\left\lbrack \frac{1}{4} - \frac{1}{9} \right\rbrack = \frac{5R}{36}$
$\therefore R = \frac{36}{5\lambda} = \frac{36}{5 \times 6563 \times 10^{- 10}} = 1.09 \times 10^{7}m^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.