Question

What is Zeroth Law of Thermodynamics?

Answer

Zeroth Law of Thermodynamics is: Two system in thermal equilibrium with a third system separately are in thermal equilibrium with each other. The Zeroth Law clearly suggests that when two systems a and B, are in thermal equilibrium, there must be a physical quantity that has the same value for both. This thermodynamic variable whose value is equal for two systems in thermal equilibrium with C, TA = TC and TB = TC. This implies that TA = TB i.e. the system A and B are also in thermal equilibrium.