Question

When an electron in H-atom jumps from $n = 4\,to\,n = 1$ , ultraviolet light is emitted, if the transition corresponds to $n = 4\,to\,n = 2$ , which of the following colours will be emitted?
A. ultra violet
B. green
C. infrared
D. no colour

Answer 1

According to the question, we should check the different types of series related to emission of lights when an electron in an H-atom jumps from higher energy level to lower energy level.

Complete Step by step answer: When an electron in H-atom jumps from n=4 to n=1, according to the Lyman Series, in this case, ultraviolet light is emitted. But, if the transition corresponds to n=4 to n=2, then according to the Balmer Series, it results in a visible region, Green light is emitted from the visible region in this case. Balmer Series is a series of visible lines of lights in the H-atom spectrum. And according to this series, when the electron jumps or we can call this electron transition from a high energy level to the lower energy level of n=2. The only difference between both the series is that when Lyman Series forms, an excited electron reaches the $n = 1$ energy level whereas when the Balmer Series forms, an excited electron reaches the $n = 2$ energy level.
So, if the transition corresponds to n=4 to n=2, then green light which is visible with naked eye will emit.

Hence, the correct option is (B). green .

Note: There are various series made to describe the transition of electrons in Hydrogen atoms such that Lyman Series, Balmer Series, Paschen Series and pfund Series. For infrared, transition occurs in paschen series.