Equilibrium refers to a state where opposing forces or processes are balanced. In thermodynamics, it occurs when a system’s properties such as pressure, temperature and volume remain constant over time. A system is in mechanical, thermal, and chemical equilibrium when no net change occurs in its state.
Class 11 Physics Chapter 11 Thermodynamics focuses on the study of heat energy and its transformation into work. It includes the first and second laws of thermodynamics the concept of entropy work done by heat engines and the Carnot cycle. The chapter also covers specific heat capacities of gases and thermodynamic processes.
The thermal equilibrium is characterized by the condition where two or more bodies in thermal contact can no longer in fact exchange heat energy, thereby reaching the same temperature. At this stage, there is no net heat flow between the systems.
How Thermal Equilibrium is Achieved:
Thermal equilibrium is achieved when:
1. Two or more objects are brought into thermal contact, which allows heat transfer.
2. Heat transfer occurs from the hotter object to the colder until both reach the same temperature.
3. Once the temperature between both gets equal, transfer of heat stops, establishing the thermal equilibrium condition.
The concept originated from Zeroth Law of Thermodynamics, which states that if two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other.