Two reversible power cycles are arranged in series. The first cycle receives energy by heat transfer from a reservoir at temperature TH and rejects energy to a reservoir at an intermediate temperature T. The second cycle receives the energy rejected by the first cycle from the reservoir at temperature T and rejects energy to a reservoir at temperature Tl lower than T. Derive an expression for the intermediate temperature T in terms of TH and Tl when (a) both engines develop equal power. (b) the thermal efficiencies of the two power cycles are equal (c) if the source and sink temperatures of 550 K and 350 K., Determine the intermediate temperature for a and b