Final answer:
The efficiency of the heat engine operating between a heat source at 325 K and a cold sink at 135 K is 58.46%.
Step-by-step explanation:
The efficiency of a heat engine can be calculated using the formula à = 1 - (Tc/Th), where à represents efficiency, Tc is the absolute temperature of the cold sink, and Th is the absolute temperature of the hot source. In this case, the heat engine utilizes thermal energy that flows from a heat source with a temperature of 325 K (Th) to a cold sink with a temperature of 135 K (Tc).
Using the formula, we calculate the efficiency as follows:
à = 1 - (Tc/Th) = 1 - (135 K / 325 K) = 1 - 0.4154 = 0.5846, or 58.46%.
Therefore, the efficiency of the heat engine under these conditions would be 58.46%.