Physics Multiple Choice Questions on “Thermal Equilibrium”.
1. Two bodies in thermal equilibrium can have different pressures. True or False?
a) True
b) False
Answer: a
Clarification: Two bodies are said to be in thermal equilibrium if they don’t exchange heat energy when they are in physical contact. For this only their temperatures have to be the same. Pressure and volume will depend upon others properties like mass.
2. The variables like pressure, volume, temperature of a thermodynamic system are microscopic. True or False?
a) True
b) False
Answer: b
Clarification: Thermodynamics does not deal with molecular descriptions. The variables it describes like pressure, volume & temperature are for a very large collection of molecules. Hence, the thermodynamic properties are macroscopic.
3. One end of a rod is held in a fire, while the other is held by one’s hand. Just assume his hand doesn’t get burned. After some time the rod-hand system is in thermal equilibrium. True or False?
a) True
b) False
Answer: b
Clarification: In the given situation, after some time a steady state will be reached. That is temperature at individual points will be constant, but there will be a difference of temperature between 2 points along the length of the rod. For, this heat flow will be continuous so we can’t call it thermal equilibrium.