Heat and Thermodynamics II - SS1 Physics Past Questions and Answers - page 4

The first law of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed in an isolated system. It can only be transferred or transformed from one form to another. This law is based on the principle of energy conservation, which states that the total energy of a closed system remains constant over time. According to the first law, the change in internal energy of a system is equal to the heat added to the system minus the work done by the system on its surroundings.

The second law of thermodynamics deals with the direction of natural processes and the concept of entropy. It states that in an isolated system, the total entropy of the system and its surroundings always increases or remains constant. Entropy is a measure of the disorder or randomness in a system. The second law implies that spontaneous processes tend to increase the overall disorder or entropy of the universe. It also provides a criterion for the direction of heat transfer, stating that heat flows spontaneously from regions of higher temperature to regions of lower temperature.