Q. Hydrogen atoms are excited from ground state of the principal quantum number 4. Then the number of spectral lines observed will be
A) 3
B) 6
C) 5
D) 2
Explanation
(b) Number of spectral lines $= \frac{n(n - 1)}{2} = \frac{4(4\ 3)}{2} = 6$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.