THE QUANTUM PHYSICS OF SOLIDS 



699 



0.5 



FERMI FUNCTION, f (E) 



Fig. 22 — Specific heat of the electrons. 



(a) Distribution of electrons in energy for the absolute zero of temperature. 



(b) Enlargement of part of (a) but for room temperature; each unit of area rep- 

 resents a quantum state. 



(c) The Fermi distribution function. 



(d) A water tank analogue. 



