Question: Which of the following statements is true according to the second law of thermodynamics?

Options:

1. Energy can be created
2. Entropy of the universe decreases
3. Heat cannot spontaneously flow from a colder body to a hotter body
4. All processes are reversible

Correct Answer: Heat cannot spontaneously flow from a colder body to a hotter body

Solution:

The second law states that heat cannot spontaneously flow from a colder body to a hotter body, which implies that entropy of the universe tends to increase.