Ionisation potential of hydrogen atom is `13.6 eV`. Hydrogen atom in ground state is excited by monochromatic light of energy `12.1 eV`. The spectral lines emitted by hydrogen according to Bohr's theory will be

Options

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

Answer

A

Explanation

Energy in the excited state = - 13.6+12.1 = - 1.5 eV
`therefore (-13.6)/(n^2) = -1.5 therefore n=3`
`therefore` 3 spectral lines will be emitted, corresponding to n = 3 to 2, n=3 to 1 and n=2 to 1
[ or `N=(n(n-1))/(2) = (3xx2)/(2) = 3` ]