Entropy occurs when sound energy changes to heat energy.

• A. It depends
• B. Only in solids
• C. True
• D. Never occurs

Answer: (C)

Entropy measures how energy becomes more dispersed and less available to do work. When sound energy is absorbed and transformed into heat in a medium, the organized motion of the sound waves is converted into random molecular motion, increasing the number of accessible microstates. That dissipation is inherently irreversible, so the overall entropy rises. This isn’t limited to solids; damping of sound into heat happens in gases, liquids, and solids alike, so the process isn’t restricted to one phase. Therefore, transforming sound energy into heat energy is a scenario that increases entropy, making the statement true. The other ideas don’t fit because real processes involve irreversible dissipation (not zero entropy change), and sound damping isn’t confined to solids.