A composite wall consisting of three different layers in perfect thermal contact is shown in the sketch below. The outer surfaces to the left and right are kept at temperatures T = 400C and T = 50C, respectively. The thickness L, and the thermal conductivity k, for i = 1, 2, 3 of each layer are also k = 20 W/(m C) T = 400C T = 50C Figure P3-47 specified. Determine the heat transfer rate.per square meter across this composite layer by assuming one-dimensional heat flow and using the thermal resistance concept.