The first law of thermodynamics gives the quantiative relations between the internal energy of a system and the quantities of heat and work that the system exchange with surroundings. It express the conservation of energy. The first law of thermodynamics is true, but not enough ! Why ? Many thermodynamic processes which don’t violate the 1st law, but don’t happen in nature ! | GENERAL PHYSICS II Electromagnetism Thermal Physics 5 6 2008 1 Chapter XVI The Second Law of Thermodynamics 1. Reversible Carnot cycles 2. The second law of thermodynamics 3. Entropy and quantitative formulation of the second law 4. Heat engines and refrigerators 5 6 2008 2 The first law of thermodynamics gives the quantiative relations between the internal energy of a system and the quantities of heat and work that the system exchange with surroundings. It express the conservation of energy. The first law of thermodynamics is true but not enough Why Many thermodynamic processes which don t violate the 1st law but don t happen in nature Examples J In an isolating system a heat transfer from the cold part to the hot part doesn t happen J No one has succeded in building a machine that converts heat completely into mechanical energy It is necessary to have a supplemental law which says about the directions of thermodynamic processes the 2nd law 5 6 2008
