Question

1. what is the state of thermal equilibrium?

options:

• when two objects in contact are at the same temperature and there is no net heat transfer between them.
• when the objects have different temperatures but no net heat transfer occurs.
• when the objects are at different temperatures but the rate of heat transfer is equal in both directions.
• when the objects have reached their lowest possible temperature.

Explanation:

To determine the state of thermal equilibrium, we recall the definition: thermal equilibrium occurs when two objects in contact have the same temperature, resulting in no net heat transfer between them.

• The first option matches this definition.
• The second option is incorrect because different temperatures would lead to heat transfer.
• The third option is incorrect as different temperatures imply a net heat transfer (even if rates in both directions are equal, a temperature difference is required for heat transfer to occur initially, and equilibrium requires same temperature).
• The fourth option is incorrect as thermal equilibrium is about same temperature, not lowest possible temperature.

Answer:

The first option (the one with "When two objects in contact are at the same temperature and there is no net heat transfer between them.")