Zeroth law of thermodynamics

Zero^th Law of Thermodynamics is also known “Law of Thermal Equilibrium”. The law states, “When two bodies are separately in thermal equilibrium with a third body, they in turn are in thermal
equilibrium with each other.”


In order to understand the zero^th law of thermodynamics. Consider two bodies ‘A’ and ‘B’ separately in thermal equilibrium with third body ‘C’ (i.e. bodies A and C have same temperature and bodies B and C have same temperature), then bodies A and B are also in thermal equilibrium with each other.