JEE Previous Year Question

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

Topic: JEE PYQ

Answer: 10. Full step-by-step solution below.