Question

A hydrogen like atom is in ahigher excitrd state of quantum no n the excited atom can make a transition to the 1st excited state by successively emiting two photons of energy 10.2ev and 17.0ev . Alternately the atom fro

Answer 1

Hey,

Total energy liberated during transition of electron from nth shell to first excited state

(i.e 2nd shell) = 10.20+17.0 = 27.20 eV

= 27.20×1.602×10−12 erg

hcλ= RH×Z2hc[122−1n2]

27.20×1.602×10−12 = RH×Z2hc[122−1n2]..... (1)

Similarly total energy liberated during transition of electrons from nth shell to second excited state

(i.e 3rd shell ) = 4.25+5.95 = 10.20 eV

= 10.20×1.602×10−12 erg

∴10.20×1.602×10−12 = RH×Z2hc[132−1n2]..... (2)

Dividing Eq (1) by Eq (2)

We get n = 6

On substituting the value of n in equation (1) or (2) we get z=3

Hence answer is (a)