Question

According to Bohr's theory, the moment of momentum of an electron revolving in the 4th orbit of a hydrogen atom is:

• A. $\frac{8h}{\pi}$
• B. $\frac{h}{\pi}$
• C. $\frac{2h}{\pi}$
• D. $\frac{h}{2\pi}$

Answer 1

Answer: (C)

$\frac{2h}{\pi}$

Answer 2

According to Bohr’s theory, the angular momentum (moment of momentum) $L$ of an electron in the $n$-th orbit is quantized and given by:
$L = \frac{n h}{2\pi},$ where $h$ is Planck’s constant and $n$ is the orbit number.

For an electron in the 4th orbit ($n = 4$):
$L = \frac{4h}{2\pi} = \frac{2h}{\pi}.$

Answer: $\frac{2h}{\pi}$