Question

Why can't a process violate the second law of thermodynamics?

Answer 1

Second law of thermodynamics

1. The second law of thermodynamics can be stated in various ways.
2. It states that any spontaneously occurring process will lead to an increase in entropy of the universe. It states that the entropy of an isolated system will never decrease over time.

The second law of thermodynamics cannot be violated because:

1. Laws of thermodynamics are universal laws that were not proven mathematically but observed.
2. Till now, nobody was able to show a case where the laws of thermodynamics were violated.
3. If it is proven that any law of thermodynamics is violated, there comes scope for new discoveries.
4. For example, if we consider the example of a heat engine, the efficiency of the heat engine is given in it as $\eta =\frac{W}{Q_H}$ Here, $\eta$ is thermal efficiency, $W$ is useful work or output obtained and $Q_H$ is the given amount of heat energy.
5. Here, you have to reject some amount of heat obtained from the combustion of fuel inside it. So here, since some amount of heat is dissipated, the second law of thermodynamics is satisfied. It is not practically possible to design an engine with no heat rejection.
6. If we consider the case of a refrigerator, too, you can't transfer heat from low to high temperatures to keep the inside of the refrigerator cooled without some external effort. This also shows that the second law of thermodynamics cannot be violated.

So, the second law of thermodynamics cannot be violated.