When two substances having different temperatures are introduced or kept together, heat energy flows from a substance at higher temperature to a substance at lower temperature. Also, heat continues to be transferred till their temperatures are equalized.
- Thermal equilibrium is the situation where there is no net heat flow between the two bodies at the same temperature.
- That is the rate of heat absorption equals to the rate of heat dissipation at the same temperature.
- Two bodies are said to be in thermal equilibrium when:
a) they are at same temperature
b) the net rate of heat flow between them is zero.
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