Written by the Fiveable Content Team • Last updated August 2025
Verified for the 2027 exam
Verified for the 2027 exam•Written by the Fiveable Content Team • Last updated August 2025
Definition
A process in which the total entropy of an isolated system remains constant; a theoretical process that occurs infinitesimally slowly and can be reversed without any net change to the universe.
AP course connection
Topic 9.6: 9.6 Entropy and the Second Law of Thermodynamics