Hydrogen atom in ground state is excited by a monochromatic radiation of `lambda = 975 Å`. Number of spectral lines in the resulting spectrum emitted will be

Options

A. 10
B. 3
C. 2
D. 6

Answer

C

Explanation

Energy of incident photon `(hc)/(lambda)=(6.63 xx 10^(-34) xx 3xx 10^(8))/(975 xx 10^(-10)xx 1.6 xx 10^(-19))e V`
which is `=12.75eV`
hence net energy becomes
`E=-0.85eV`
which corresponds to 4th state hence number of spectral lines
`=(n(n-1))/(2) =(4(4-1))/(2) =6`.