When is thermal equilibrium achieved between two objects?

A.
when thermal energy is no longer transferred

B.
when one objects is hotter than the other

C.
when both objects have the same temperature

D.
when the particles in one object have more kinetic energy

Question

When is thermal equilibrium achieved between two objects?
  
 
 

 
 

  

  A. 
  when thermal energy is no longer transferred   
   

 
 

  

  B. 
  when one objects is hotter than the other   
   

 
 

  

  C. 
  when both objects have the same temperature   
   

 
 

  

  D. 
  when the particles in one object have more kinetic energy

anonymous · Answer

A

farcher · Answer

Interesting question in that two of the answers are correct.
The zeroth law of thermodynamics states that if body A is in thermal equilibrium with body C, (which means the bodies are joined together and there is no net heat or thermal energy transfer between them), and if body B is in thermal equilibrium with body C then bodies A and B would be in thermal equilibrium if they are joined together.

If body C is a thermometer then what this law says that bodies at the same temperature if joined together will be in thermal equilibrium.

You will note that there are two "correct" answers.

isaiah.feynman · Answer

I agree with @Farcher .A and C are the same phenomena. When thermal energy is no longer transferred, the two objects have the same temperature and vice versa. This is the zeroth law of thermodynamics.

anonymous · Answer

i agree with both... but it is not given that both are connected directly may be there is any adiabatic medium between them... so here ans c is correct.

farcher · Answer

@amitsilswal
" may be there is any adiabatic medium between them" is of no relevance.
The question asks about two bodies being in thermal equilibrium.  This implies that there is no transfer of "heat" between the two bodies.

anonymous · Answer

ya rye