Question

The wave length of first member of Balmer series of a hydrogen atom is nearly (The value of Rydberg constant is $1.08\times {10}^7{m}^{-1})$

• A. 4400A°
• B. 5500A°
• C. 6600A°
• D. 7700A°

Answer 1

The correct option is C

6600A°

$n_1=2$ $n_2=3$

$\frac{1}{\lambda }=R[\frac{1}{4}-\frac{1}{9}]$

$\lambda =\frac{36}{5R}=\frac{36}{5\times 1.08\times {10}^7}m$

= $\frac{36}{5\times 1.08}\times {10}^{-7}m$

$\approx 6600A^0$