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Wave Optics

Question
CBSEENPH12038597

In Bohr's theory of hydrogen atom, calculate the energy of the photon emitted during a transition of the electron from the first excitated state to its ground state. Write in which region of the electromagnetic spectrum this transition lies.
Given Rydberg constant R = 1.03 × 107 m–1.

Solution
Energy for nth level of hydrogen atom is given by, 

                      En = -13.6n2eV 

Energy of the photon emitted during a transition of the electron from the first excited state (n=2) to its ground state (n=1) is, 

 E = E2 - E1    = -13.622--13.612    = -13.64+13.61    = -3.40+13.6     = 10.2 eV 

This transition lies in the region of Lyman series.