Which of the transitions in hydrogen atom emits a photon of lowest frequency (n = quantum number)
Answer & explanation
Correct answer: option 2
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.