Determine the amount of heat given by the internal combustion engine

Determine the amount of heat given by the internal combustion engine to the refrigerator, if its efficiency is 30%, and the useful work is 450 J.

We calculate the efficiency of an internal combustion engine using the formula:

η = (Ap / Q) * 100%, where η is the engine efficiency (η = 30% = 0.3), Ap is the useful work (Ap = 450 kJ), Q is the total amount of heat received by the engine (Q = Q1 + Q2, where Q1 = Ap, Q2 is the amount of heat given to the refrigerator).

Let us express and calculate the amount of heat given to the refrigerator:

η = (An / (An + Q2)) * 100%.

Q2 = Ap / η – Ap = 450 / 0.3 – 450 = 1050 J.

Answer: The amount of heat given to the refrigerator is 1050 J.