Question

In terms of Rydberg constant R, the wavenumber of the first Balmer line is:

• A. R
• B. 3R
• C. $\frac{5R}{36}$
• D. $\frac{8R}{9}$

Answer 1

Answer: (C)

Wave number $\bar{v}=\frac{1}{\lambda }=R\left(\frac{1}{{n_1}^2}-\frac{1}{{n_2}^2}\right)$ Here, $n_1=2,n_2=3$ $\therefore$ $\bar{v}\frac{5R}{36}$