Question

When a hydrogen atom emits a photon of energy 12.1 eV, the oribital angular momentum changes by:

• A. $\frac{h}{2\pi }$
• B. $\frac{3h}{2\pi }$
• C. $\frac{h}{\pi }$
• D. $\frac{2h}{\pi }$

Answer 1

The correct option is C $\frac{h}{\pi }$

Energy difference of 12.1 eV is possible for $3\to 1$.
By bohr's model,
Angular momentum of electron in any orbit is $nh/2\pi$.
$\Delta L=(3-1)h/2\pi$.