Question

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

(1) \(8 \frac{\mathrm{h}}{\pi}\)

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

(3) \(2 \frac{\mathrm{h}}{\pi}\)

(4) \(\frac{\mathrm{h}}{2 \pi}\)

Answer 1

Correct option is : (3)  \(2 \frac{\mathrm{h}}{\pi}\)   

Moment of momentum is \(\overrightarrow{\mathrm{r}} \times \overrightarrow{\mathrm{P}}\)

\(\overrightarrow{\mathrm{L}}=\overrightarrow{\mathrm{r}} \times \mathrm{m} \overrightarrow{\mathrm{v}}\)

\(\mathrm{L}=\mathrm{mvr}=\frac{\mathrm{nh}}{2 \pi}=\frac{4 \mathrm{h}}{2 \pi}=\frac{2 \mathrm{h}}{\pi}\)