Identify the matter waves with the shortest wavelength when traveling at the same speeds.

1. Electron

2. Alpha particle (He2+)

3. Neutron

4. Proton

Hint: De brogile equation

From de-Broglie equation,
wavelength, λ=hmv
For the same speed of different particles, i.e., electron, proton, neutron and α-particle,
λ1m
As h is constant. Greater the mass of matter waves, lesser is wavelength and vice-versa. In these matter waves, alpha
particle (He2+) has a higher mass, therefore, shortest wavelength.