How fast does a proton have to be moving is order to have the same de Broglie wavelength as an electron that is moving at 3.90 × 10⁶ m/s?
The speed of the proton must be 2.12 ×10³ m/s.
The de Broglie equation is
2.12 ×10³ m/s
This makes sense. A proton has about 2000 times the mass of an electron, so it would have to travel at about ¹/₂₀₀₀ the speed of an electron to have the same momentum —
Hope this helps.