When the conduction electrons in a metal are treated as an ideal gas of fermions, the mean number of electrons occupying a state with energy e is given by i+ (-2) (3)u (a) define the fermi energy [ marks] (b) sketch n as a function of e for an electron gas: (i) at t 0 k, and to the fermi temperature (ii) at a temperature above 0 k, but small compared label and briefly justify each sketch [5 marks] (c) describe the change in the variation of n with e as the temperature increases, and hence explain why conduction electrons make only a small contribution to the heat capacity of a metal at room temperature