Thermal Properties of Matter – Notes

Temperature and heat
Heat is defined as a form of energy that flows from hotter body to a colder body when they are in thermal contact.
When two bodies are in thermal contact and there is no net exchange of heat, then they are said to be in thermal equilibrium.
The physical quantity that is the same for the systems in thermal equilibrium is temperature.
The SI unit of heat is “joule” and temperature is “Kelvin”.

Ideal gas equation and absolute temperature
Gas thermometers are used to get accurate temperature readings of a body.
Boyle’s law: if the temperature of a given mass of gas is constant, then its pressure is inversely proportional to its volume.
Charles; law: At constant pressure, the volume of a given mass of gas is directly proportional to its temperature, T.
An ideal gas equation is: PV=µRT
The relation between the absolute temperature and Celsius temperature is expressed as: T =tc+ 273.15

Thermal expansion
An increase in the dimensions of a body due to an increase in its temperature is called thermal expansion.