Final answer:
The efficiency of the engine is calculated using the formula Efficiency = (Work output / Heat input) × 100%. Assuming the heat input is the sum of the work done and the heat rejected to the cold reservoir, the efficiency is found to be approximately 35.75%.
Step-by-step explanation:
To calculate the efficiency of an engine, we can use the formula:
Efficiency = (Work output / Heat input) × 100%
In the scenario provided, the given heat rejected to the cold reservoir is 2,185 J, and the work performed is 1,216 J. However, we need the total heat input to find the efficiency.
If we assume that the heat rejected to the cold reservoir and the work done are the only forms of energy transfer, then the heat input can be calculated as the sum of work done and heat rejected:
Heat input = Work done + Heat rejected = 1,216 J + 2,185 J = 3,401 J
Now, we can calculate the efficiency:
Efficiency = (1,216 J / 3,401 J) × 100% ≈ 35.75%
The engine's efficiency is approximately 35.75% in this case.