Welcome to Fullonstudy. Today we are going to discuss another important topic called the Zeroth law of Thermodynamics. In this article, we will discuss some important questions based on Thermal equilibrium and the Zeroth law of thermodynamics.
1. What is thermal equilibrium?
2. Explain the Zeroth law of Thermodynamics.
According to Zeroth’s law “If two systems ‘A’ and ‘B’ are separately in thermal equilibrium with a third system ‘ C’, then the two systems ‘A’ and ‘B’ are also in thermal equilibrium with each other”.
Now If adiabatic wall between systems A and ‘B’ is replaced by a diathermic wall, experiments show that no further changes occur in systems A and ‘B’ indicating thereby that system A was also in thermal equilibrium with system B. This important experimental fact leads us to follow general conclusion :
If two systems are in thermal equilibrium with a third system, then they must be in thermal equilibrium with each other.
This statement is called Zeroth’s law of thermodynamics.
If the there is no change in length of mercury thread on placing the thermometer C either in contact of the gas vessel containing A or that of the vessel containing B is brought in thermal contact with each other. This is in accordance with Zeroth’s law.