The top layer of your goose down sleeping bag has a thickness of 5.4cm and a surface area of 1.0 m^2. When the outside temperature is -19C you lose 25 cal/hr by heat conduction through the bag (which remains at a cozy 35C inside). Assume that you're sleeping on an insulated pad that eliminates heat conduction to the ground beneath you.
What is the thermal conductivity of the goose down?