# Both The Nucleus And The Atom Of Some Elements Are In Their Respective First Excited States. They Get De-excited By Emitting Photons Of Wavelengths 𝝀N, 𝝀a Respectively. The Ratio 𝝀n/𝝀a Is Closest To :

$\frac{E_{A}}{E_{B}} = \frac{\frac{hc}{\lambda_{A}}}{\frac{hc}{\lambda_{N}}}$

So,

$\frac{E_{A}}{E_{N}} = \frac{\lambda_{N}}{\lambda_{A}}$

As order of EA = ev

As order of EN = Mev

Therefore,

$\frac{\lambda_{N}}{\lambda_{A}} \\= \frac{1ev}{1Mev}\\= \frac{1}{10^{6}} = 10^{-6}$

Explore more such questions and answers at BYJU’S.