Heat and Thermodynamics

2.1 Introduction

When we touch ice, we feel cold; when we stand in the sun, we feel hot. Our sense can perceive these conditions. To quantify the extent of hotness and coldness, we need to know the degree of hotness and coldness which is measured by a physical entity called temperature. The instrument by which temperature is measured is called a thermometer. A hotter body is at a higher temperature. If two bodies are at the same temperature, then they are in thermal equilibrium. If a third body is of the same temperature as the two bodies described earlier, then all the three bodies are in thermal equilibrium. This is the Zeroeth law of thermodynamics. Temperature of a body is measured based on this law.

When we heat a body, different changes ...