Heat Engines Practice
10 problems · instant feedback · full explanations
Engines turn heat into work but must dump waste heat. Carnot efficiency η = 1 − Tc/Th is the ceiling — no engine beats it.
Q1.
Thermal efficiency of a heat engine is defined as:
Multiple choice · Easy
Q2.
An engine takes in 800 J, expels 500 J as waste heat. What is its efficiency? (%)
Numerical answer (%) · Medium
Q3.
What is the maximum efficiency between 600 K and 300 K reservoirs? (%)
Numerical answer (%) · Medium
Q4.
Carnot efficiency must be computed with temperatures in:
Multiple choice · Easy
Q5.
How does a refrigerator move heat from a cold interior to a warm room?
Multiple choice · Medium
Q6.
A heat pump moves 400 J from outside using 100 J of work. What is its coefficient of performance?
Multiple choice · Hard
Q7.
A steam engine works between 1200 K and 300 K. What is its Carnot limit? (%)
Numerical answer (%) · Hard
Q8.
All real heat engines must reject some waste heat to a cold reservoir.
True / False · Easy
Q9.
Carnot efficiency depends on the type of fuel burned in the engine.
True / False · Medium
Q10.
Diesel engines are more efficient than gasoline engines mainly because of:
Multiple choice · Hard