A doubled layered wall has layer A, 10 cm thick and B, 20 cm thick. The thermal conductivity of A is thrice that of B. In the steady state, the temperature difference across the wall is 35 oC. The temperature difference across the layer A is

Question

A doubled layered wall has layer A, 10 cm thick and B, 20 cm thick. The thermal conductivity of A is thrice that of B. In the steady state, the temperature difference across the wall is 35 oC. The temperature difference across the layer A is (A)  28 oC  (B)  14 oC  (C)  7 oC  (D)  5 oC

Tardigrade Admin · Accepted Answer

In the steady state, rate of heat across each layer of the wall is the same (KAA(Δ T)/10)=(KBA(35-Δ T)/20) using KA=3KB we get Δ T=5 oC

Q. A doubled layered wall has layer A, 10 cm thick and B, 20 cm thick. The thermal conductivity of A is thrice that of B. In the steady state, the temperature difference across the wall is $35^{o} C .$ The temperature difference across the layer A is

$28^{o} C$

$14^{o} C$

$7^{o} C$

$5^{o} C$

In the steady state, rate of heat across each layer of the wall is the same
$\frac{K _{A} A ( Δ T )}{10} = \frac{K _{B} A ( 35 - Δ T )}{20}$
using $K_{A} = 3 K_{B}$
we get $Δ T = 5^{o} C$

Q. A doubled layered wall has layer A, 10 cm thick and B, 20 cm thick. The thermal conductivity of A is thrice that of B. In the steady state, the temperature difference across the wall is 35oC. The temperature difference across the layer A is

28oC

14oC

7oC

5oC