De Broglie wavelength and ideal gas entropy derivation

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1. Feb 18, 2015

predaylight

When the ideal gas entropy is derived, we consider N atoms in a box of volume=Lx*Ly*Lz. Then, we make the assumption that Lx,Ly,Lz >>de Broglie wavelength of atoms. I am not sure why we need to make this assumption? Thanks!

2. Feb 19, 2015

Bystander

How many energy levels are available in a box of dimensions equal to the deBroglie wavelength?