Physics•Hard

Heat Engine Efficiency

Physics challenge: A Carnot heat engine operates between a hot reservoir at 600 K and a cold reservoir at 300 K.

Scenario

You are analyzing the theoretical maximum efficiency of heat engines. The Carnot cycle sets the upper limit — real engines always fall below this due to irreversible processes.

Scored questions

Question 1

What is the Carnot efficiency of this engine? (T_hot = 600 K, T_cold = 300 K)

Question 2

If the engine absorbs 800 J per cycle from the hot reservoir, what is the maximum work output per cycle?

Question 3

Heat is rejected to the cold reservoir each cycle. How much heat is rejected?

Question 4

The Second Law of Thermodynamics states that the entropy of an isolated system:

Always decreasesAlways increases or remains constantRemains exactly constantCan be reversed by doing work

Answer keys, scoring tolerance, XP, and awards stay on the server. Retrying the same attempt cannot award twice.

Open related simulation →