Asmall oxidized horizontal metal tube is placed in a very large furnace enclosure with firebrick walls. the metal tube has an outside diameter of 1.5 inch and a length of 3 ft. a surface emissivity of 0.7 and its surface is maintained at 650° f. the hot air in the furnace is 1500° f and the furnace brick walls are at 1350° f. the convection heat transfer coefficient for the horizontal tube is 3.0 btu/h. ft2. calculate: (a) the convective, radiative and total heat transferred to the metal tube (b) the percent of total heat transferred by radiation (c) the radiation heat transfer coefficient