Question

Out of electron and proton, which will have a higher velocity to produce matter waves of the same wavelength? why?!

Answer 1

The de-broglie relationship is given by

$\text{λ =}\frac{\text{h}}{\text{mv}}$

where $\text{λ}$ is wavelength, m is mass and v is velocity.
We can also write the relation as

$\text{v =}\frac{\text{h}}{\text{mλ}}$

So, velocity is inversely proportional to the mass.
mass of electron = 9.1$\times$10^-31kg

mass of proton = 1.6$\times$10^-27kg

Mass of proton is more than mass of electron therefore the velocity of electron is more than that of proton.