Question

A proton and an electron have same velocity. Which one has greater de-Broglie wavelength and why?

Answer 1

The de-Broglie wavelength λ is given for mass m and velocity v of a particle as

`lambda=h/(mv)`

Now for an electron and proton velocity v is given same.

Since m_p > m_e

We have inverse relations of λ and mass

So λ_p < λ_e

Thus electron would have greater wavelength than wavelength of proton accelerated with same velocity.