Q. Which of the transitions in hydrogen atom emits a photon of lowest frequency ($n =$ quantum number)
A) $n = 2$ to $n = 1$
B) $n = 4$ to $n = 3$
C) $n = 3$ to $n = 1$
D) $n = 4$ to $n = 2$
Explanation
(b) From diagram
$E_{1} = - 13.6 - ( - 3.4) = - 10.2eV$
$E_{2} = - 13.6 - ( - 1.51) = - 12.09eV$
$E_{3} = - 1.51 - ( - 0.85) = - 0.66eV$
$E_{4} = - 3.4 - ( - 0.85) = ( - 2.55)eV$
$E_{3}$ is least, $i.e.,$ frequency is lowest
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.