Question

The angular momentum of an electron in (i) 2s orbital (ii) 4f orbital respectively are:

• A. 0 and $\sqrt{12}\frac{h}{2\pi }$
• B. $\sqrt{12}\frac{h}{2\pi }$ and $\sqrt{6}\frac{h}{2\pi }$
• C. $\sqrt{12}\frac{h}{2\pi }$ and $\sqrt{20}\frac{h}{2\pi }$
• D. None of these

Answer 1

The correct option is A 0 and $\sqrt{12}\frac{h}{2\pi }$

As we know,
Angular momentum of electron in any orbital=$\sqrt{l(l+1)}\frac{h}{2\pi }$
for 2s, $l=0$ so
angular momentum of electron in 2s orbital=$0$
for 4f, $l=3$ so
Angular momentum of electron in 4f orbital=$\sqrt{12}\frac{h}{2\pi }$