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Three identical rods A, B and C are placed end to end. A temperature difference is maintained between the free ends of A and C. The thermal conductivity of B is thrice that of C ands half of that of A. The effective thermal conductivity of the system will be (K_(A) is the thermal conductivity of rod A) |
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Answer» `1/3K_(A)`  Given, `K_(B)=K_(A)//2` and `K_(B)=3K_(C)` `:.K_(C)=K_(A)//6` Rods are in series from so `(L)/(K)=(l_(1))/(K_(A))+(l_(2))/(K_(B))+(l_(3))/(K_(C ))""(becausel=l_(1)=l_(2)=l_(3))` `(3l)/(K)=(l)/(K_(A))+(l)/(K_(1)//2)+(l)/(K_(A)//6)` or `(3l)/(K)=(9L)/(K_(A))` or `K=(K_(A))/(3)` So, correct choice is (a). |
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