5. The most important contribution to the paramagnetism of copper sulphate(CuSO,) comes from the Cu ions which have spin 1/2 and may be considered to be non-interacting. (a) Show that the magnetization in a field B is given by M = NUBtanh(UBB/KBT) where N is the number of ions per unit volume and /, is the Bohr magneton. (b) Derive the "high " temperature form of the magnetic specific heat in a constant magnetic field. (c ) What is a "high" temperature if B = 0.5 T ? (d) What is the spin entropy