Zeroth Law And Thermal Equilibrium
Two blocks A and B are each found to be in thermal equilibrium with a third block C, yet A and B are never placed in direct contact with each other. What can be concluded about A and B?
Select the correct option:
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More thermodynamics Practice Questions
Three metal blocks P, Q and R are kept in contact such that P is in equilibrium with Q and Q is in e...
Three metal blocks P, Q and R are kept in contact such that P is in equilibrium with Q and Q is in e...
When 2 moles of a monatomic ideal gas are heated at constant pressure causing a temperature rise of ...
When 2 moles of a monatomic ideal gas are heated at constant pressure causing a temperature rise of ...
Two identical samples of the same ideal gas are kept at the same temperature but stored at very diff...
Two identical samples of the same ideal gas are kept at the same temperature but stored at very diff...
On a pressure-volume diagram an isothermal curve and an adiabatic curve pass through the same point ...
On a pressure-volume diagram an isothermal curve and an adiabatic curve pass through the same point ...
For a diatomic ideal gas the molar specific heat at constant volume is 5R/2, so what is the value of...
For a diatomic ideal gas the molar specific heat at constant volume is 5R/2, so what is the value of...
A heat pump uses 200 J of work to deliver a total of 800 J of heat into a warm room during each oper...
A heat pump uses 200 J of work to deliver a total of 800 J of heat into a warm room during each oper...
Two moles of an ideal gas expand isothermally at 300 K from a volume V to a volume 2V in a slow reve...
Two moles of an ideal gas expand isothermally at 300 K from a volume V to a volume 2V in a slow reve...
A balloon suddenly bursts and the compressed gas inside rushes out into the open atmosphere very rap...
A balloon suddenly bursts and the compressed gas inside rushes out into the open atmosphere very rap...
A gas is taken around a complete thermodynamic cycle and returns to its original state after several...
A gas is taken around a complete thermodynamic cycle and returns to its original state after several...
A heat engine absorbs 1000 J of heat from a hot reservoir and rejects 600 J to the cold reservoir in...
A heat engine absorbs 1000 J of heat from a hot reservoir and rejects 600 J to the cold reservoir in...
The efficiency of a Carnot engine is 40 percent when the sink temperature is 300 K, so to what tempe...
The efficiency of a Carnot engine is 40 percent when the sink temperature is 300 K, so to what tempe...
An ideal gas expands at a constant pressure of 2 × 10^5 Pa, increasing its volume from 0.01 m^3 to 0...
An ideal gas expands at a constant pressure of 2 × 10^5 Pa, increasing its volume from 0.01 m^3 to 0...
About This Question
- Subject
- physics
- Chapter
- thermodynamics
- Topic
- zeroth law and thermal equilibrium
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
They must be at the same temperature
The Zeroth Law of Thermodynamics states that if two systems are each separately in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law is what allows temperature to be defined as a consistent property: thermal equilibrium is a transitive relationship. Here A is in equilibrium with C and B is in equilibrium with C, so by the Zeroth Law A and B share the same temperature even though they were never touched together. Equal heat capacities is incorrect because heat capacity depends on mass and material, not on temperature alone. Equal internal energy is incorrect because internal energy also depends on the amount and nature of the substance, so two bodies at the same temperature can store very different energies. The claim that nothing can be concluded is wrong precisely because the Zeroth Law removes the need for direct contact. As a consistency check, temperature is the unique quantity that becomes equal at equilibrium, confirming the conclusion.
This easy difficulty physics question is from the chapter thermodynamics, covering the topic of zeroth law and thermal equilibrium. It appeared in the 2025 exam.
Looking for more practice? Explore all physics questions or browse thermodynamics questions on RankGuru.