Let `E=(-1me^(4))/(8epsilon_(0)^(2)n^(2)h^(2))` be the energy of the `n^(th)` level of H-atom state and radiation of frequency `(E_(2)-E_(1))//h` falls on it ,

Options

A. it will not be absorbed at all
B. some of atoms will moves to the first excited state .
C. all atom will be excited to the `n=2` state
D. no atom will make a transition to the `n=3` state.

Answer

B, D

Explanation

Given `E_(n)=(-1me^(4))/(8epsilon_(0)^(2)n^(2)h^(2))` Energy of incident radiation `E_(2)-E_(1)=hv=-3.40-(-13.6)=10.2eV`
the energy is sufficient to move some of atom in ground state `(E_(1)` to the first excited state `(E_(2)`, not atom shall make transition to `n=3` state be -cause energy required for transition to `n=3` is `12.09eV`