What is the efficiency of a heat engine if it receives an amount of heat equal to 6 kJ

What is the efficiency of a heat engine if it receives an amount of heat equal to 6 kJ from the heater and gives the refrigerator an amount of heat equal to 4.8 kJ?

These tasks: Qн (heat received by the used heat engine from the heater) = 6 kJ; Qx (heat given to the refrigerator) = 4.8 kJ.

The efficiency of the used heat engine is calculated by the formula: η = (Qн – Qх) / Qн.

Let’s make a calculation: η = (6 – 4.8) / 6 = 0.2 (20%).

Answer: The used heat engine has an efficiency of 20%.