A furnace is shaped like a long equilateral triangular duct - in which a heated surface(left surface) is maintained at 1200K and another surface (right surface) is insulated. Bottom surface is maintained at 500K. The triangle is of width W⁻¹m on a side, and the heated and insulated surfaces have an emissivity of 0.8. The emissivity of bottom surface is 0.4 . During steady - state operation, what rate of heat energy must be supplied to the heated side (per unit length of the duct) to maintain its temperature at 1200K?
