Solution:
Kinetic energy of any particle=
Also K.E.=
De-broglie wavelength
=
mass of thermal neutron > mass of thermal electron > mass of visible photon
order of debroglie wavelengths is Visible photon > Thermal electron > Thermal neutron
At temperature T, the average kinetic energy of any particle is (3/2) KT. The de Broglie wavelength follows the order:
Kinetic energy of any particle=
Also K.E.=
De-broglie wavelength
=
mass of thermal neutron > mass of thermal electron > mass of visible photon
order of debroglie wavelengths is Visible photon > Thermal electron > Thermal neutron