Question

The difference between orbital angular momentum of an electron in a $4f$ orbital and another electron in a $4s$ orbital is:

• A. $2\sqrt{3}$
• B. $3\sqrt{2}$
• C. $\sqrt{3}$
• D. $2$

Answer 1

The correct option is A $2\sqrt{3}$

Orbital angular momentum is given by the formula,
$\sqrt{l(l+1)}.\frac{h}{2\pi }$
$\therefore$ For $4f,l=3$
$\Rightarrow \text{orbital angular momentum}=\sqrt{12}.\frac{h}{2\pi }$
For $4s,l=0$,
$\Rightarrow \text{orbital angular momentum}=0$
$\therefore \text{Difference}=\sqrt{12}-0=\sqrt{12}=2\sqrt{3}$