The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively, are\[{{\operatorname{T}}_{2}}\] and \[{{T}_{1}}\]\[({{\operatorname{T}}_{2}}>{{T}_{1}})\]. The rate of heat transfer through the slab, in a steady state is \[\left( \frac{A\left( {{\operatorname{T}}_{2}}>{{T}_{1}} \right)K}{x} \right)f\], with f equal to

The temperature of the two outer surfaces of a composite slab, consist

1.	The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively, are\[{{\operatorname{T}}_{2}}\] and \[{{T}_{1}}\]\[({{\operatorname{T}}_{2}}>{{T}_{1}})\]. The rate of heat transfer through the slab, in a steady state is \[\left( \frac{A\left( {{\operatorname{T}}_{2}}>{{T}_{1}} \right)K}{x} \right)f\], with f equal to
A.	\[\frac{2}{3}\]
B.	\[\frac{1}{2}\]
C.	1
D.	\[\frac{1}{3}\]
Answer» E.