Question

In a hydrogen like atom, when an electron jumps from the $M$ - shell to the $L$ - shell, the wavelength of emitted radiation is $\lambda$. If an electron jumps from $N$-shell to the $L$-shell, the wavelength of emitted radiation will be :

• A. $\frac{27}{20} \lambda$
• B. $\frac{16}{25} \lambda$
• C. $\frac{20}{27} \lambda$
• D. $\frac{25}{16} \lambda$

Answer 1

Answer: (C)

$\frac{20}{27} \lambda$

Answer 2

For $M \to L$ steel
$\frac{1}{\lambda} =K \left(\frac{1}{2^{2}} - \frac{1}{3^{2}}\right) = \frac{K\times5}{36}$
for $N\to L$
$\frac{1}{\lambda'} =K \left(\frac{1}{2^{2}} - \frac{1}{4^{2}}\right) = \frac{K\times3}{16}$
$\lambda' = \frac{20}{27} \lambda$