Question

The wave number of first line in Balmer series of hydrogen spectrum is (Rydberg constant, $R_H=109,687c{m}^{-1}$) nearly

• A. $82,259c{m}^{-1}$
• B. $152,00c{m}^{-1}$
• C. $97,492c{m}^{-1}$
• D. $15,200c{m}^{-1}$

Answer 1

Answer: (B)

$152,00c{m}^{-1}$

$\begin{array}{c}\text{Wave number}\\ \text{Here,}[\overline{v}=R_H{z}^2[\frac{1}{n_i{}^2}-\frac{1}{n_2^2}]\\ R_H=109687\\ z=1\end{array}$

$\begin{array}{c}\text{Balmar}{n}_1=2\text{, and}{n}_2=3\\ \overline{v}=109687[\frac{1}{(2{)}^2}-\frac{1}{(3{)}^2}]\\ \overline{v}=109687[\frac{1}{4}-\frac{1}{9}]\end{array}$

$\overline{v}=15200{cm}^{-1}$