In a mixture of `He^(o+)` gas H atom and `He^(o+)` ions Are excited to three respective first excited subsepuenly , H atom transfers its total excitation energy to `He^(o+)`ions by collision .Assuming that Bohr model of an atom is applicable , answer the following question
If each hydrogen atom in the ground state of `1.0 mol ` of H atom is excited by absorbing photon of energy `8.4 eV, 12.09 eV` and `15.0 eV` of energy then the number of spectral lines emitted is equal to

Options

A. 5
B. 2
C. 3
D. 4

Answer

C

Explanation

Ground state electron in H atom can only be excited by energy greater than `0.2 eV` Thus, `15 eV` photon energy will ionic the atom and `8.4 eV`photon will not be able to higher palte ,New this will be excited to `n = 3` During de-excitation , corresponding to three transition wavelength will be emitted
`{:(-0.85 eV .........n = 4),(-1.51 eV .........n = 3),(-3.4 eV .........n = 2),(-13.6 eV .........n = 1):}`