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

Options

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

Answer

C

Explanation

`E_n=(-13.6)/n^2` eV
For ground state `DeltaE_1`=13.6 eV
Energy of photon, `DeltaE`=12.1 eV
`DeltaE=E_n-E_1`
`12.1=E_n-(-13.6)`
`E_n`=1.5 eV
`(-13.6)/n^2=-1.5` eV
`n^2=9`
n=3
Electron is excited to third orbit
Spectral line will be `(3(3-1))/2=3`