When Two bodies at different temperatures T₁ and T₂ if brought in thermal contact , heat flows from the body at higher temperature to the body at lower temperature , till both attain thermal equilibrium or we can say temperature of both become same and equal to the mean temperature (T₁ + T₂ )/2 . but this is not always the case if heat capacities of the both the bodies is not same. since we know amount of heat transferred to a body is proportional to its heat capacity , so if heat capacity of one body is less than that of other it will absorb less heat and temperature of both will not become equal and both will not settle to the mean temperature (T₁ + T₂ )/2