Question

A proton and an electron have the same kinetic energy. Which one has a greater de Broglie wavelength? Justify.

Answer 1

de-Broglie wavelength of the particle is λ = `"h"/"p" = "h"/sqrt(2"mK")`

i.e. `λ ∝ "h"/sqrt"m"`

As for m_e << m_p, so λ_e >> λ_p

Hence protons have a greater de-Broglie wavelength.