A particle having electric charge 3 × 10^-19 C and mass 6 × 10^-27 kg is accelerated by applying an electric potential of 1.21 V. Wavelength of the…

A particle having electric charge $\displaystyle 3 \times 10^{-19} \mathrm{C}$ and mass $\displaystyle 6 \times 10^{-27} \mathrm{~kg}$ is accelerated by applying an electric potential of $\displaystyle 1.21$ V. Wavelength of the matter wave associated with the particle is $\displaystyle \alpha \times 10^{-12} \mathrm{~m}$. The value of $\displaystyle \alpha$ is $\displaystyle \_\_\_\_$. (Take Planck's constant $\displaystyle =6.6 \times 10^{-34} \mathrm{~J} . \mathrm{s}$ )