Q. Four lowest energy levels of $H$-atom are shown in the figure. The number of possible emission lines would be
A) 3
B) 4
C) 5
D) 6
Explanation
(d) Number of possible emission lines $= \frac{n(n - 1)}{2}$
Where $n = 4$; Number $= \frac{4(4 - 1)}{2} = 6$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.