Question

An electron is moving in the third orbit of an atom whose radius is $r$. The de Broglie wavelength associated with electron is

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

Answer 1

The correct option is D $\frac{2\pi r}{3}$

$mvr=\frac{3h}{2\pi }$
$\frac{2\pi r}{3}=\frac{h}{mv}=\frac{h}{p}=\lambda$
$\lambda =\frac{2\pi r}{3}$