The configuration of a furnace can be approximated as an equilateral triangular duct which is sufficiently long that the end effects are negligible. The hot wall is maintained at T1 = 1000 K and has an Emissivity e1 = 0.8. The cold wall is at T2 = 500 K and has an Emissivity e2 = 0.8. The third wall is reradiating zone for which Q3 =0. Calculate the net radiation flux leaving the hot wall.