Question

According to Bohr's theory, the moment of momentum of an electron revolving in the 4^th 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

The Correct Option is C

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: \(\frac{2h}{\pi}\)