Question

If two objects are in thermal equilibrium with each other

• A. They can’t be moving
• B. They can’t be undergoing an elastic collision
• C. They can’t have different pressures
• D. They can’t be at different temperatures

Answer 1

The correct option is D

They can’t be at different temperatures

The explanation for the correct answer:

Option D

1. When two or more bodies are kept in thermal contact transfer of energy from one to another takes place due to their temperature difference and this transfer continues until both the bodies are at the same temperature.
2. Once the bodies acquire the same temperature, no transfer of energy takes place between them and the bodies are said to be in thermal equilibrium.
3. Therefore, if two objects are in thermal equilibrium with each other they can’t be at different temperatures.
4. Hence, Option (D) is the correct answer.

The explanation for incorrect answers:

Option A

1. Thermal equilibrium as defined is a condition where two physically connected bodies stop heat exchange. It is not related to motion. Therefore, option A is incorrect.

Option B

1. An elastic collision is the collision of two bodies with no kinetic energy loss. It too is not related to thermal equilibrium. So option B is also incorrect.

Option C

1. Thermal equilibrium does not define the pressure of the bodies. Hence, option C is also incorrect.