Ionization potential of hydrogen atom is `13.6 V`. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy `12.1 eV`. The spectral lines emitted by hydrogen atoms according to Bohr's theory will be

Options

A. two
B. three
C. four
D. one

Answer

B

Explanation

Ionization enegry corresponding to ionization potential `=- 13.6 eV`
Photon enegry incident `= 121eV`
So, the energy of electron in excited state
`=- 13.6 + 12.1 =- 1.5 eV`
`rArr E_(n) =- (13.6)/(n^(2))eV - 1.5 = (-13.6)/(n^(2))`
`n^(2) = (-13.6)/(-1.5) ~~9 :. n = 3`
That is enegry of electron in excited state corresponds to third orbit.
The possible spectral lies are when electron jumps from orbit `3dr` to `2nd`, to `1`st and `2`st. Thus, `3` spectral lines are emitted.