Question

Chapter 13, Problem 08 GO A closed box is filled with dry ice at a temperature of -81.6 °C, while the outside temperature is 16.3 °C. The box is cubical, measuring 0.397 m on a side, and the thickness of the walls is 4.36 x 10-2 m. In one day, 3.46 x 106 J of heat is conducted through the six walls. Find the thermal conductivity of the material from which the box is made. Units Number the tolerance is +/-6% LINK TO TEXT

Answer 1

here,

for the total surface area

A = 6 * 0.397^2

A = 0.946 m^2

let the thermal conductivity of the material is a

for the heat flow rate

Q/time = a * Area * difference in temperature/thickness

3.46 *10^6/(24 * 3600) = a * 0.946 * (16.3 - (-81.3))/(4.36 *10^-2)

solving for a

a = 0.0189 W/(m.K)

the thermal conductivity of the material is 0.0189 W/(m.K)