Question

Increasing entropy in the universe means that

• A. Organisms can use the energy released to break down food products.
• B. There is increasing amounts of heat energy and small particles of matter becoming disordered.
• C. Reactions cannot occur spontaneously.
• D. The entropy in a system also must increase.

Answer 1

Answer: (D)

The entropy in a system also must increase.

Universe contains hot objects like star and cold objects like planets. Stars are radiating energy into the universe and hence we can say entropy of the universe is always increasing

Let's consider $S_1$ be the entropy of hot region

$S_1=\frac{q}{T_1}$

and $S_2$ be the entropy of cold region

$S_2=\frac{q}{T_2}$

$△S=S_2-S_1=\frac{q}{T_2}-\frac{q}{T_1}=q(\frac{1}{T_2}-\frac{1}{T_1})$

Since $T_2<T_1$, then

$\frac{1}{T_1}<\frac{1}{T_2}$

Hence total energy of the system increases

Hence increasing entropy in the universe means entropy in the system must increases