In your own words define thermal equilibrium. (Be very careful of your use of th
ID: 2003118 • Letter: I
Question
In your own words define thermal equilibrium. (Be very careful of your use of the word heat. It is perhaps the most abused word in our physics lexicon. To a physicist, heat has the definition of energy in transit from a high temperature object to a low temperature object. A key part of the definition is the prepositional phrase in transit. Bodies do not possess heat, they do however posses internal energy. Internal energy is the random motion of the molecules and atoms. People typically mean internal energy when they use the word heat. Notice that the correct definition of the word heat describes just one way to add energy to a body. We can increase the internal energy in other ways.) If a container of orange juice is not in thermal equilibrium with the air in the kitchen and a container of milk is in thermal equilibrium with the orange juice what can you say about the temperatures of the three thermal systemsExplanation / Answer
(a) Thermal equilibrium exists when two objects in thermal contact no longer affect each other's temperature. For example, if a carton of milk from the refrigerator is set on the kitchen countertop, the two objects are in thermal contact. After several hours, their temperatures are the same, and they are then in thermal equilibrium.
(b) The temperature of container of orange juice and container of milk is same as they are in thermal equilibrium. However their temperature is different from the air in the kitchen as they are not in thermal equilibrium with the air.