You Are Testing Thermal Conduction Through a Composite Material Made $\circ$

Multiple Choice

You are testing thermal conduction through a composite material made up of two layers, A and B. Layer A is twice as thick as layer B, and the thermal conductivity of material A is three times higher than that of material B. If the temperature on the outside surface of A is 80 ^$\circ$ C, and the temperature on the outside surface of B is 10 ^$\circ$ C, find the temperature at the interface of the two materials once a steady state of heat flow has been established.

A) 44 ^$\circ$ C
B) 52 ^$\circ$ C
C) 70 ^$\circ$ C
D) 12 ^$\circ$ C
E) 47 ^$\circ$ C