(a) Show that all reversible engines operating between the same source and sink will have same efficiency.

(b) A reversible heat engine operates between two reservoirs at temperature of 600^oC and 40^oC. The engine drives a reversible refrigerator which operates between reservoirs at temperature of 40 ^oC and -20 ^oC. The heat transfer to the heat engine is 2000kJ and total work output of the combined engine refrigerator plant is 360KJ.

(i ) Determine the heat transfer to the refrigerant and net heat transfer to the reservoir at 40 ^oC.

(ii) Reconsider (i) given that the efficiency of the heat engine and the COP of the refrigerator are each 40% of their maximum possible values.