Thermal Equilibrium

For the objects in thermal equilibrium, the amount of heat energy present in both the objects is same.

Under what conditions, a system is said to be in thermal equilibrium?

What happens to the macroscopic variables in a system that is in thermal equilibrium?

Explain with example how the concept of thermal equilibrium is related to the zeroth law of thermodynamics.

A system is in thermal equilibrium with its environment if

Two bodies are said to be in thermal equilibrium when

Three bodies $A, B$ and $C$ are in thermal equilibrium the temperature of $B$ is $45{ }^{\mathrm{o}}\mathrm{C}.$ Then the temperature of $C$ is :

Two rigid boxes containing different ideal gases are placed on table. Box A contains one mole of nitrogen at temperature $T_0$ , while box B contains 1 mole of helium at temperature $\frac{7}{3}{T}_0.$ The boxes are then put into thermal contact with each other and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes) then the final temperature of gases, $T_f$ in terms of $T_0$ is

Assertion: Two metallic spheres of same size, one of copper and the other of aluminum, heated to the same temperature, will cool at the same rate when they are suspended in the same enclosure.

Reason: The rate of cooling of a body is directly proportional to the excess of temperature of the body over the surroundings.