The velocities of two particles $\underline {A}$ and $\underline {B}$ are $00.05$ and $0.02\;ms^{-1}$ respectively. The mass of $\underline {B}$ is five times the mass of $\underline {A}$. The ratio of their de Broglie's wavelength is

Question

\[\begin {array} {1 1} (1)\;2:1 & \quad (2)\;1:4 \\ (3)\;1:1 & \quad (4)\;4:1 \end {array}\]