Two physical systems are in thermal equilibrium when ______.

Two physical systems are in thermal equilibrium when ______.

a. No heat flows between them when they are connected by a path permeable to heat
b. Heat flows continuously from one system to another with a constant rate.
c. Temperature as well as pressure remains constant in both the systems.
d. None of above.

Correct Answer : a. No heat flows between them when they are connected by a path permeable to heat

Explanation :

Thermal equilibrium between two or more bodies exists when they are brought together and there is no flow of heat energy. Only the temperature is constant.