Two rods $A$ and $B$ of different materials are welded together as shown in figure.Their thermal conductivities are $K_1$ and $K_2$ The thermal conductivity of the composite rod will be
NEET 2017, Medium
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Eqiuivalent thermal conductivity of the composite rod in parallel combination will be,
$K = \frac{{{K_1}{A_1} + {K_2}{A_2}}}{{A{ _1} + {A_2}}} = \frac{{{K_1} + {K_2}}}{2}$
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