Entropy
Entropy is a function of a quantity of heat which shows the possibility of conversion of that heat into work. The increase in entropy is small when heat is added at a high temperature and is greater when heat is added at a lower temperature. Hence for maximum entropy, there is minimum availability for conversion into work and for minimum entropy there is maximum availability for conversion into work.
Entropy may also be defined as the thermal property of a substance which remains constant when substance is expanded or contracted adiabatically in a cylinder.
Characteristics of Entropy :
- It increases when heat is supplied irrespective of rise in temperature.
- It decreases when heat is removed irrespective of fall in temperature.
- It remains unchanged in all adiabatic frictionless processes.
