If travelling at same speeds, which of the following matter waves have the shortest wavelength ?

If travelling at same speeds, which of the following matter waves have

1.	If travelling at same speeds, which of the following matter waves have the shortest wavelength ?
Answer» Electron Alpha particle `(He^(2+))` Neutron Proton Solution :According to de-Broglie equation, wavelength, `lambda=(h)/(MV)`For same speed of different PARTICLES, i.e., electron, proton, neutron and `alpha` particle `lambda` particle `lambda prop (1)/(m)` h is CONSTANT. So, GREATER the mass of matter waves, lesser is wavelength and vice-versa. In these matter waves, alpha particle `(He^(2+))` has higher mass, therefore, shortest wavelength.