The change in entropy of the engine is equal to the heat energy absorbed divided by the temperature at which the heat transfer occurs. In this case, the change in entropy is 120 J divided by the temperature (T) ΔS = 120 J / T.
The change in entropy of the engine can be calculated using the equation:
ΔS = Q / T
Where ΔS is the change in entropy, Q is the heat energy absorbed by the engine, and T is the temperature at which the heat transfer occurs.
In this case, the engine absorbs 120 J of heat energy during an isothermal expansion. Since the process is isothermal, it means that the temperature remains constant throughout the expansion. Let's assume the temperature is T.
Using the formula, we can calculate the change in entropy:
ΔS = 120 J / T