An outer wall of a furnace is at '7'„,' Kelvin and it faces an environment at '1' e' . The wall's average convective heat transfer coefficient 'h' is 4 W/m2K. For radiation heat transfer, the wall's...

An outer wall of a furnace is at '7'„,' Kelvin and it faces an environment at '1' e' . The wall's average convective heat transfer coefficient 'h' is 4 W/m2K. For radiation heat transfer, the wall's emissivity 'e' equals its absorbity 'a' and equals 0.8. The ratio of net heat loss by radiation to heat loss by convection from the wall is closed to