`1^(st)` excitation Potential of a hydrogen like sample is 15 volt. If all the atoms of the sample are in `2^(nd)` excited state then find the `K.E.` in `eV` of the electron ejected if a photon of energy `(65)/(9)eV` is supplied to this sample.

Options

A. 5
B. 2
C. 6
D. 4

Answer

1

Explanation

`15eV=13.6Z^(2)xx(3)/(4)" "rArr13.6Z^(2)=20eV`
Energy of 2nd excited state `=(13.6Z^(2))/(3^(2))=(-20)/(9)eV, :. K.E.` of electron `=(65)/(9)-(20)/(9)=(45)/(9)=5eV`