Question

What is the basis for measuring thermodynamic property of temperature?

Answer 1

We must know that Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy present in all matter, which is the source of occurrence of heat, a flow of energy. It’s measured in various scales like Celsius and Fahrenheit.

Complete answer:
Firstly we need to understand the concept of Zeroth law of thermodynamics which states that “If two thermodynamic systems are in thermal equilibrium with a third system, then these two system will also be in thermal equilibrium with each other”. Let us understand by an example: Suppose we have three bodies A B and C , Now it’s given that body A and B are in thermal equilibrium with body C then According to Zeroth law of thermodynamics Body A and B will also in thermal equilibrium with each other.

Zeroth law is also the most fundamental law of thermodynamics even when other two laws, First law of thermodynamics and Second law of thermodynamics were established before the Zeroth law of thermodynamics. So, temperature according to this law is taken as thermodynamic property. The zeroth law justifies the use of suitable thermodynamic systems as thermometers to provide such a labelling, which yields any number of possible empirical temperature scales.

Note: Two systems are said to be in relation to thermal equilibrium if they are linked by a wall permeable only to heat and they do not change over time. The most common scales to measure thermometers are Celsius denoted as $^0C$ and Fahrenheit denoted as $^0F$.