Question

Which of the following statements is true?
A.The total entropy of the universe remains constant.
B.The total entropy of the universe is continuously decreasing.
C.The total energy of the universe is continuously decreasing.
D.The total energy of the universe remains constant.

Answer 1

Hint: The mentioned options are related to the thermodynamic process. These are based on laws of thermodynamics mainly the first law of thermodynamics. The first law of thermodynamics is the version of law of conservation of energy.

Complete step by step answer:
First, let us discuss the first law of thermodynamics. It differentiates the two types of transfer of energy, and it states that the total energy of an isolated system is constant.
1.Now, if seeing the options first is related to the entropy of the universe, it relates to the second law of thermodynamics.
2.As we know according to the second law, the total entropy of the universe is continually increasing.
3.So, we can conclude the first, and second option is wrong.
4.Talking about the third and fourth option, both are based on the total energy of the universe.
5.As mentioned according to the first law it remains constant.
6.Thus, the correct statement is the total energy of the universe remains constant. The correct option is D.

Note: As mentioned the second law of thermodynamics is based on entropy, but it is different for reversible, and irreversible processes. In the reversible process, there is no net change in entropy, whereas in an irreversible process, it is always increasing. Thus, the overall total entropy of the universe increases. There is no need to get confused in between these both processes.