3. Steam at a temperature of 250C flows through a steel pipe (AISI 1010) of 60-mm inside diameter and 75-mm outside diameter. The convection coefficient between the steam and the inner surface of the pipe is 500 W/mK, while that between the outer surface of the pipe and the surroundings is 25 W/mK. The pipe emissivity is 0.8, and the temperature of the air and the surroundings is 20C. What is the heat loss per unit length of pipe? We wish to determine the effect of adding a layer of magnesia insulation to the steam pipe of the foregoing problem. The convection coefficient at the outer surface of the insulation may be assumed to remain at 25 W/mK, and the emissivity is 0.8. Determine and plot the heat loss per unit length of pipe as a function of outer radius for 38 mm to 75 mm.