In a fully degenerate gas, all the particles have energies lower than the Fermi energy For such a gas we found (Eq, 4.19) the relation between the density n, and the Fermi momentum p: 8T 3h3 PF a. For a non relativistic electron gas, use the relation pF = /2m between the Fermi momentum, the electron mass me, and the Fermi energy Er, to express Ef in terms of ne and me b. Estimate a characteristic ne under typical conditions inside a white dwarf. Using the result of (a), and assuming a temperature T 107 K, evaluate numerically the ratio Eth/EF, where Eth is the characteristic thermal energy of an electron in a gas of temperature T, to see that the electrons inside a white dwarf are indeed degenerate.