Find effective thermal resistance between $A$ & $B$ of cube made up of $12$ rods of same dimensions and shown given thermal conductivity. [ $l =$ length of rod, $a =$ cross section area of rod]
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Let $\mathrm{R}=\frac{1}{\mathrm{K}} \cdot \frac{l}{\mathrm{a}}$
$R_{e q}=\frac{R}{2}=\frac{1}{2}\left(\frac{\ell}{k a}\right)$
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