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Wave Optics

Question
CBSEENPH12038595

The energy of the electron, the hydrogen atom, is known to be expressible in the form
En = -13.6 eVn2    (n =1, 2, 3, ....)
Use this expression to show that the
(i) electron in the hydrogen atom can not have an energy of – 2 V.
(ii) spacing between the lines (consecutive energy levels) within the given set of the observed hydrogen atom spectrum decreases as n increases.


Solution

Energy for the hydrogen atom is given by,
 
         En = -13.6 eVn2 

Putting n = 1, 2, 3............n,  we get

                            E1 = -13.612 = -13.6 eVE2 = -13.622=-13.64=3.4 eVE3 = -13.632=-13.69= -1.51 eV 

E4 = -13.642=-13.616= -.85 V..........................................................................En = -13.62 = 0 eV

(i) Hence, from the above expressions it can be observed that the electron in the hydrogen atom cannot have an energy of – 2V.

(ii) As n increases, energies of the excited states come closer and closer together. Therefore, as n increases, En becomes less negative until at n = ∞, we get En = 0.