Question

A closed box is filled with dry ice at a temperature of -81.5 C, while the outside temperature is 27.4 C. The box is cubical, measuring 0.307 m on a side, and the thickness of the walls is 4.47 × 10-2 m. In one day, 3.37 × 106 J of heat is conducted through the six walls. Find the thermal conductivity of the material from which the box is made.