A wall has two layers A and B each made of different materials. The layer A is 10cm thick and B is 20 cm thick. The thermal conductivity of A is thrice that of B. Under thermal equilibrium temperature difference across the wall is `35^@C`. The difference of temperature across the layer A isA. `28^(@)C`B. `14^(@)C`C. `7^(@)C`D. `5^(@)C`

A wall has two layers A and B each made of different materials. The la

1.	A wall has two layers A and B each made of different materials. The layer A is 10cm thick and B is 20 cm thick. The thermal conductivity of A is thrice that of B. Under thermal equilibrium temperature difference across the wall is `35^@C`. The difference of temperature across the layer A isA. `28^(@)C`B. `14^(@)C`C. `7^(@)C`D. `5^(@)C`
Answer» Correct Answer - D In the state, rate of heat across each layer of the wall is the same. `(K_(A)A(DeltaT))/(10) = (K_(B)A(35-DeltaT))/(20)` Using `K_(A) = 3K_(B)`, solving , `Delta T = 5^(@)C`

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