A composite wall consists of two plates A and B placed in series normal to the flow of heat. The thermal conductivities are kA and kB and the specific heat capacities are CPA and CPB for plates A and B respectively. Plate B has twice the thickness of plate A. At steady state, the temperature difference across plate A is greater than that across plate B, when_________________?
Correct answer: C
Explanation
The temperature drop is proportional to thickness divided by conductivity. For the temperature difference across A to be greater than B, we need kA < 0.5 kB.