Final answer:
The engine with the highest efficiency is engine 4.
Step-by-step explanation:
The efficiency of an engine can be calculated using the formula e = Wout/Qin, where e is the efficiency, Wout is the work output, and Qin is the heat input.
The engine with the highest efficiency is the one that has the highest ratio of work output to heat input.
In this case, we need to calculate the efficiency of each engine by dividing the work output (Qh - Qc) by the heat input (Qh). Then, we can compare the calculated efficiencies to determine which engine has the highest efficiency:
Engine 1: Efficiency = (5.68E6 - 3.81E6) / 5.68E6 = 33.64%
Engine 2: Efficiency = (9.21E6 - 8.30E6) / 9.21E6 = 10.00%
Engine 3: Efficiency = (5.32E5 - 2.32E5) / 5.32E5 = 56.38%
Engine 4: Efficiency = (3.10E5 - 1.20E5) / 3.10E5 = 61.29%
Therefore, engine 4 has the highest efficiency.