Third Semester

Thermodynamics owes its origin to the attempt to convert heat energy into mechanical work and to develop the theory of operation of devices for this purpose. Two fundamental concepts in thermodynamics are work and heat. The zeroth law establishes the existence of thermal equilibrium and allows the temperature to be measured using a thermometer. The first law places work and heat as the only way the internal energy of a system or a body can be increased. The second law talks about the entropy of a system. The first and second laws explain the operations of the Carnot engine, real heat engines, and refrigerators. Refrigerators are devices used to cool a body system, and the process of doing this is called the refrigeration cycle. These three laws of thermodynamics, i.e., zeroth, first, second, are based on the observations made in the field of thermodynamics.