Question

An electron and a proton are moving with the same velocity, v. Find their phase and group velocities of
their de Broglie waves respectively.

Answer 1

As election and proton are moving with same velocity = v

So their group velocity = v (as we know that particle velocity= group velocity)

So both election and proton have group velocity =v

Now relation between group velocity and phase velocity is : group velocity* phase velocity= c^2

Where c=speed of light =3*10^8 m/s

So phase velocity of electron and proton = c^2 /v

Answer: group velocity of electron and proton = v

Phase velocity of electron and proton=c^2 /v

Thank you.