Here’s a explanation of the Second Law of Thermodynamics:
Statement:
- Heat naturally flows from a hot object to a cold object.
- No process can convert all heat into work; some energy is always lost as waste heat.
- In other words, entropy (disorder) of the universe always increases in spontaneous processes.
Key Points:
- Direction of Processes:
- Explains why some processes happen naturally (e.g., ice melting) and others do not (e.g., water spontaneously freezing at room temperature).
- Efficiency Limit:
- Sets the maximum efficiency of heat engines; no engine can be 100% efficient.
- Entropy Concept:
- Entropy measures disorder or randomness.
- In any real process, total entropy increases.
Simple Example:
- When you put a hot cup of tea in a cold room, heat flows to the room.
- You cannot spontaneously make the room heat the tea without adding energy.
In short: The second law explains the direction of energy flow, limits of efficiency, and the increase of disorder in the universe.