Question

If a proton and an electron have the same de Broglie wavelength, then:

• A. kinetic energy of electron < kinetic energy of proton
• B. kinetic energy of electron = kinetic energy of proton
• C. momentum of electron = momentum of proton
• D. momentum of electron < momentum of proton

Answer 1

The correct option is C momentum of electron = momentum of proton

de Broglie wavelength, $\lambda =\frac{h}{p}$ where p is the momentum of the particle For electron, ${\lambda }_e=\frac{h}{p_e}$
For proton, ${\lambda }_p=\frac{h}{P_p}$
As ${\lambda }_e={\lambda }_p\Rightarrow P_p=P_p$
or Momentum of electron = Momentum of proton