Answer the problem with the problem data, please.

Heat transfer

Consider a plane wall of a material with a thermal conductivity that varies with the cube of the temperature according to the relationship = ₀(1 + ³).

a) Get a expression for the heat transfer of heat in this wall, is a constant

b) determine the heat flux [W] through a plane wall of thermal conductivity ₀ of 0.72 W/m C, and temperatures on the inner and outer surface of 60C and 25 C, respectively. The wall thickness is 20 cm, heat transfer area of 16 m² and of 1.5 W/K^3.