Question

The angular momentum of an electron in Bohr's hydrogen atom whose energy is $-3.4eV$, is

• A. $\frac{5h}{2\pi }$
• B. $\frac{h}{2\pi }$
• C. $\frac{h}{\pi }$
• D. $\frac{2h}{3\pi }$

Answer 1

Answer: (C)

$\frac{h}{\pi }$

Energy of electron in nth orbit of hydrogen atom
$E_n=-\frac{13.6}{n^2}eV$
$\Rightarrow 3.4=-\frac{13.6}{n^2}\Rightarrow n^2=4$
or, $n=2$
Angular momentum of electron,
$L=\frac{nh}{2\pi }=\frac{2h}{2\pi }=\frac{h}{\pi }$