Suppose that in some sample the density of states of the electrons $D(\varepsilon)$ is a constant $D_0$ for energy $\varepsilon>0(D(\varepsilon)=0$ for $\varepsilon<0)$ and that the total number of electrons is equal to $N$.
(a) Calculate the Fermi potential $\mu_0$ at 0 K .
(b) For non-zero temperatures, derive the condition that the system is non-degenerate.
(c) Show that the electronic specific heat is proportional to the temperature, $T$, when the system is highly degenerate.