What is the de Broglie wavelength (in nm) of a proton of traveling at 3.18% of the speed of light?

Answer is: de Broglie wavelength of a proton is 3,4·10⁻⁵ nm.

v (proton) = 0,038 · 3·10⁸ m/s.

v (proton) = 1,14·10⁷ m/s; speed of proton.

m (proton) = 1,67·10⁻²⁷ kg.

h = 6,62607004·10⁻³⁴ m²·kg/s; Planck constant.

λ (proton) = h / m (proton) · v (proton).

λ (proton) = 6,62607004·10⁻³⁴ m²·kg/s : (1,67·10⁻²⁷ kg · 1,14·10⁷ m/s).

λ (proton) = 3,48·10⁻¹⁴ m · 10⁹ nm/m = 3,4·10⁻⁵ nm.