(b) The typical de Broglie wavelength, , is given as 2 = h 3mkBT where m is the mass of a particle, kB is the Boltzmann's constant and T is the temperature in Kelvin. If the lattice spacing in a typical solid is around d = 0.3 nm, find the temperature below which the system in a solid stated in (i) and (ii) is quantum mechanical. (i) (ii) (iii) The unbound electrons (outermost electrons) The nuclei of sodium atom (mass of sodium nuclei is 23 times mass of the proton) What is the conclusion that can be derived from the answer (i) and (ii)?