Problem 2 A binary alloy is composed of N4 atoms of type A and of Np atoms of type B. Each A-type atom can exist in its ground state or in an excited state of energy . Each B-type atom similarly can exist in its ground state of energy zero or in an excited state of energy 2. The system is at equilibrium at temperature T. a) Calculate the Helmholtz free energy F, internal energy U and entropy S of the system. b) Calculate the heat capacity of the system