# Which electronic level would allow a H-atom to absorb a photon but not to emit a photon ?

$(a)\;3s\qquad(b)\;2p\qquad(c)\;1s\qquad(d)\;3d$

Solution :
At ground state i.e at level 1, H-atom can absorb an photon but not emit an photon.
It can reach a higher level by absorbing photon but there is no lower , so it can not emit photon .
edited Nov 17, 2017 by meena.p