Which principle states that no process can reduce the entropy of an isolated system?

The principle that states no process can reduce the entropy of an isolated system is rooted in the second law of thermodynamics. This law introduces the concept of entropy as a measure of energy dispersal within a system, indicating that natural processes tend to proceed in a direction that increases the total entropy of an isolated system.

In simpler terms, when energy transformations occur, they are not 100% efficient - some energy is always dispersed as waste heat, leading to increased disorder or entropy in the system. This law implies that while energy can change forms, the overall trend in an isolated system will always move towards greater entropy, reinforcing the idea that processes cannot spontaneously lead to a decrease in entropy without external influence.

The first law of thermodynamics, often referred to as the law of energy conservation, deals with the conservation of energy and does not specifically address the concept of entropy. The zeroth law focuses on thermal equilibrium and temperature, while the third law pertains to the behavior of systems as they approach absolute zero, discussing how entropy approaches a minimum value at this extreme. Hence, it is the second law that directly relates to the unyielding nature of entropy in isolated systems.