At temperature T, the average kinetic energy of any particle is 3/2kT. The de Broglie wavelength follows which of the following order?

K.E = 3/2kT = 1/2mV² = 1/2P²/m. Here P is the momentum. Also the de Broglie wavelength λ = h/mV = h/P. Thus a particle having lower mass will have higher velocity and lower momentum. Its de Broglie wavelength will be higher. Hence, the de Broglie wavelength follows the order Visible photon > Thermal electron > Thermal neutron.