Thermal equilibrium

Definition

Thermal equilibrium is the state in which two or more objects in thermal contact no longer exchange heat, resulting in a uniform temperature throughout the system. This occurs when the temperatures of the objects are equal.

5 Must Know Facts For Your Next Test

1. Thermal equilibrium follows from the Zeroth Law of Thermodynamics, which states that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
2. When two objects are in thermal equilibrium, their temperatures are equal and there is no net flow of heat between them.
3. Achieving thermal equilibrium can involve energy transfer via conduction, convection, or radiation until uniform temperature is reached.
4. In thermodynamic systems, reaching thermal equilibrium is crucial for defining properties such as temperature and internal energy.
5. The concept of thermal equilibrium is fundamental to understanding processes like phase changes and heat engines.

Review Questions

• What condition must be met for two objects to be in thermal equilibrium?
• How does the Zeroth Law of Thermodynamics relate to thermal equilibrium?
• What happens to the net flow of heat when two systems reach thermal equilibrium?

Related terms

Zeroth Law of Thermodynamics: If two thermodynamic systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.

Conduction: The process by which heat energy is transmitted through collisions between neighboring atoms or molecules.

Internal Energy: The total energy contained within a system due to both its microscopic kinetic and potential energies.