SOLVED:Fermi Surface in the Free Electron (Sommerfeld) Theory of Metals (a) Explain what is meant by the Fermi energy, Fermi temperature and the Fermi surface of a metal. (b) Obtain an expression for the Fermi wavevector and the Fermi energy for a gas of electrons (in 3D). D Show that the density of states at the Fermi surface, d N / d EF can be written as 3 N / 2 EF. (c) Estimate the value of EF for sodium [The density of sodium atoms is roughly 1 gram/cm ^3, and sodium has atomic mass of rough