A stainless steel pipe (k= 17 W/m?C) is being used to convey heated oil. The inside surface temperature is 130?C. The pipe is 2 cm thick with an inside diameter of 8 cm. The pipe is insulated with 0.04 m thick insulation (k= 0.035 W/mC). The outer insulation temperature is 25?C. Calculate the temperature of interface between steel and isulation. Assume steady-state conditions.