Question

What are the difference between thermal expansion and thermal equilibrium

Answer 1

Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature.(eg: if you heat any metal (say iron) you can see there will be a small increase in its length. This is Thermal expansion)

Thermal equilibrium:Two physical systems are in thermal equilibrium if no heat flows between them when they are connected by a path permeable to heat.(eg: if there are two glasses of hot tea. one have 20 degree temperature and other have 30 degree temperature. now we mix these 2 glasses into a single cup then the resulting temperature is the equilibrium temperature between these two glasses of tea. Now we say they are in thermal equilibrium)