Question

In a H - atom, the transition takes place form L to K shell. If R = $1.08\times {10}^7{m}^{-1}$. The wave length of the light obsorbed in nearly:

• A. 4400 A⁰
• B. 1250 A⁰
• C. 1650 A⁰
• D. 1850 A⁰

Answer 1

The correct option is B

1250 A⁰

$n_1=1$,$n_2=2$

$\frac{1}{\lambda }$=$R$($\frac{1}{1^2}$-$\frac{1}{2^2}$)

$\lambda$=$\frac{4}{3R}$=$\frac{4}{3\times 1.08\times {10}^7}$

=$\frac{4}{3.24\times {10}^7}$$\times {10}^{10}$

=1250$A^{\circ }$