A heat engine operates on the following three-step cycle: 1

PHYSICS · Single correct · A Level · Physics · Engineering physics · Engineering physics

Problem

A heat engine operates on the following three-step cycle: 1. Isothermal expansion at

600\,\text{K}

from

0.010\,\text{m}^3

0.030\,\text{m}^3

does

1.7\,\text{kJ}

of work BY the gas and absorbs

1.7\,\text{kJ}

of heat. 2. Adiabatic compression returns the gas to

0.010\,\text{m}^3

while

1.0\,\text{kJ}

of work is done ON the gas; no heat is exchanged. 3. The gas is cooled at constant volume back to its initial state; no work is done in this step and heat is rejected. What is the thermal efficiency

\varepsilon = W_{\text{out}}/Q_{\text{in}}

of the engine? (a)

0.59

(b)

0.29

(c)

0.41

(d)

0.70

Related theory

First Law of Thermodynamics
Laws of Thermodynamics
Heat Engines
Second law and Carnot cycle
Thermodynamics
Carnot engine

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