Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature T₀ , while Box B contains one mole of helium at temperature (7 / 3) T₀ . 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 the gases, T_f , i