Question

The velocities of two particles $A$ and $B$ are $0.05$ and $0.02$ $m{s}^{-1}$ respectively. The mass of $B$ is five times the mass of $A$. The ratio of their de-Broglie's wavelength is :

• A. $2:1$
• B. $1:4$
• C. $1:1$
• D. $4:1$

Answer 1

The correct option is A $2:1$

$\lambda =\frac{h}{mv}$

The ratio of their de-Broglie's wavelength is:

$\frac{\lambda }{{\lambda }^{\prime }}=\frac{m^{\prime }{v}^{\prime }}{mv}=\frac{5m\times 0.02}{m\times 0.05}=\frac{2}{1}$

Hence, option A is correct.