The temperature of the two outer surfaces of a composite slab, consisting of two materails having coefficients of two materails having coefficients of termal conductivity K and 2K and thickness x and 4x, respectively, are `T_2 and T_1(T_1gtT_1)`. The rate of heat transfer through the slab, in a steady state is `((A(T_2-T_1)K)/2)f`, with f equal to A. `2/3`B. `1/2`C. `1`D. `1/3`

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 materails having coefficients of two materails having coefficients of termal conductivity K and 2K and thickness x and 4x, respectively, are `T_2 and T_1(T_1gtT_1)`. The rate of heat transfer through the slab, in a steady state is `((A(T_2-T_1)K)/2)f`, with f equal to A. `2/3`B. `1/2`C. `1`D. `1/3`
Answer» Correct Answer - D (d) The thermal resistance `x/(KA)+(4x)/(2KA)=(3x)/(KA)` `:. (dQ)/(dt)=(DeltaT)/((3x)/(KA))=((T_2-T_1)KA)/(3x)=1/3{(A(T_2-T_1)K)/x}` `:. f=1/3`

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