Question

a certain electronic transition from an excited state to ground state of hydrogen atom in one or more steps give rise to 4 lines in the ultraviolet region of the spectrum how many lines does this transition produced in the infrared region of the spectrum

Answer 1

Four lines are observed in the ultraviolet region of the spectrum. Thus the series is Lyman. These corresponds to the transitions 5 --->1 , 4--->1 , 3---->1 , 2---->1 The possible transitions in the IR region are 5 ----->4 (Brackett series) 5----->3 , 4----->3 (paschen series)

Thus, in the infrared region of the spectrum, 3 lines are produced.