In a particular nuclear reaction, electrons and alpha particles are emitted, with the electrons having twice the speed of the alpha particles. An alpha particle is made of two neutrons and two protons. It is known that mproton ≈ mneutron ≈ 1,836 melectron.
The ratio of the de Broglie wavelength of an electron over the de Broglie wavelength of an alpha particle is most closely equal to: