In a composite slab, the temperature at the interface (Tinter) between two materials is equal to the average of the temperatures at the two ends. Assuming steady one-dimensional heat conduction, which of the following statements is true about the respective thermal conductivities?
A. 2K1=K2 B. K1=K2 C. 2K1=3K2 D. K1=2K2
The answer is D.