A replace poker consists of a wrought iron rod, 50 cm long and 5 cm2 in cross-section, fused to a piece of cork 10 cm long (with the same cross-section). The thermal conductiv- ities of (this grade of ) iron and cork are 60 and 0.06 W/(m·C, respectively. One end of the poker is in a ?re at a temperature of 700 C while the other end is at 30 C. Estimate the temperature at the iron-cork boundary?