If a proton and an electron have the same de Broglie wavelengths, which one is moving faster?
A) the proton
B) the electron
C) They both have the same speed.

Question

Quizplus · Accepted Answer

The electron is moving faster because the de Broglie wavelength ($\lambda$) is inversely proportional to the momentum (p) of the particle ($\lambda = \frac{h}{p}$), where $h$ is Planck's constant. Since the proton has much more mass than the electron, for them to have the same wavelength, the electron must have a higher velocity to compensate for its much smaller mass.

If a Proton and an Electron Have the Same De