Question

In a $H$-atom, the n transition takes place from $L$ to $K$ shell If $R=1.08\times 1067m^{-1}$, the wave length of the light emitted is nearly:

• A. $4400A^o$
• B. $1250A^o$
• C. $1650A^o$
• D. $1850A^o$

Answer 1

Answer: (B)

$1250A^o$

For $K$ and $L$ shell corresponding principal quantum number is $n=1$ and $n=2$.

Transition is from $n_2=2$ to $n_1=1$

$\frac{1}{\lambda }=R[\frac{1}{n_1^2}-\frac{1}{n_2^2}]$

Substituting $n_1=1$, $n_2=2$ and $R=1.09\times {10}^7{m}^{-1}$

$\lambda =\frac{4}{3R}$

$\lambda =1250A^0$