A circular tube of outer diameter 5 cm and inner diameter 4 cm is used to convey hot fluid. The inner surface of the wall of the tube is at a temperature of 800C, while the outer surface of the wall of the tube is at 250C. What is the rate of heat transport across the tube wall per meter length of the tube of steady state, if the thermal conductivity of the tube wall is 10 W/(mK) ?