123-2 Determination of Thermal Conductivity: In determining the thermal conductivity (k) of an insulating material, the temperatures were measured on both sides of a flat slab of 25 mm of the material and were 318.4 and 303.2 K. The heat flux was measured 35.1 W/m². Calculate the thermal conductivity in Btu/(h·F) and in W/m·K.