A) \[{{70}^{o}}C\]
B) \[{{50}^{o}}C\]
C) \[{{60}^{o}}C\]
D) \[{{90}^{o}}C\]
Correct Answer: A
Solution :
Key Idea: In steady state rate of flow of heat is same in both the conductors. Let 6 be steady temperature of the interface, the rate of flow of heat is \[H=\frac{Q}{t}={{K}_{1}}\,A\frac{({{\theta }_{1}}-\theta )}{l}=\frac{{{K}_{2}}A(\theta -{{\theta }_{2}})}{l}\] Given, \[{{K}_{1}}:{{K}_{2}}=5:3,\,{{\theta }_{1}}={{100}^{o}}C,{{\theta }_{2}}={{20}^{o}}C\] \[\therefore \] \[5(100-\theta )=3(\theta -20)\] \[\Rightarrow \] \[500-5\theta =3\theta -60\] \[\Rightarrow \] \[8\theta =560\] \[\Rightarrow \] \[\theta ={{70}^{o}}C\]You need to login to perform this action.
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