Question

The energy levels of an atom of elements X are shown in the diagram. Which one of the level transitions will result in the emission of photons of wavelengths 620 nm? Support your answer with mathatical calculations.​

Answer 1

Transition D happened

Answer 2

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Energy of emitted photo,

$\implies$ E = $\frac{hc}{\lambda}$

$\implies$ E = $\frac{6.6 × 10^-34 × 3 × 10^8}{620 × 10^-9}$ J

$\implies$ E = 3.2 × ${10^-19}$ J

$\implies$ E = $\frac{3.2 × 10^-19}{1.6 × 10^-19}$ eV = 2eV

This energy corresponds to the transition D for which energy change = -1-(-3) = 2 eV.