Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Atoms

Question:

Which of the transitions in hydrogen atom emits a photon of lowest frequency (n = quantum number)

Options:

n = 2 to n = 1

n = 4 to n = 3

n = 3 to n = 1

n = 4 to n = 2

Correct Answer:

n = 4 to n = 3

Explanation:

From diagram

$E_1=-13.6-(-3.4)=-10.2 eV$

$E_2=-13.6-(-1.51)=-12.09 eV$

$E_3=-1.51-(-0.85)=-0.66 eV$

$E_4=-3.4-(-1.51)=-1.89 eV$

$E_3$ is least i.e. frequency is lowest.