o As thermal equilibrium obeys the zeroth law of thermodynamics, temperature of system and surroundings will be the same when they are in thermal equilibrium.

• Thermal equilibrium is defined as the point when two physical systems (here system and the surroundings) are brought into a connection that does not allow the transfer of matter or any kind of energy between them, such a connection is said to permit the transfer of energy as heat.

• when such a connection is made between two physical systems and the making of the connection is followed by no change of state of the either, then the two systems are said to be in relation of thermal equilibrium, and that means the system and surroundings both will have the same temperature.