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Two sheets of thickness d and 3d and of same area are joined together. Temperature `T_(A), T_(B), T_(C )` shown in the figure are in geometric progression with common ration `r = 3`. Then ratio of thermal conductivity of thinner to thicker sheet is A. 1B. 2C. 3D. 4 |
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Answer» Correct Answer - A `T_(B) = 3T` `T_(C ) 3T_(B) = 9T_(A)` In steady state `P_("in") = P_("out")` `= K_(2) A_(1) ((T_(B) - T_(C ))/(3d)) = - K_(1) A ((T_(A) - T_(B))/(d))` `(K_(2))/(3) (-6T_(A)) = K_(1) (-2T_(A))` `2K_(2) = 2K_(1)` `(K_(1))/(K_(2)) = (1)/(1)` |
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