A slab consists of two parallel layers of two different materials of same thickness having thermal conductivities $K_1$ and $K_2$ . The equivalent conductivity of the combination is
A slab consists of two parallel layers of two different materials of same thickness having thermal conductivities $K_1$ and $K_2$ . The equivalent conductivity of the combination is
- A
${K_1} + {K_2}$
- B
$\frac{{{K_1} + {K_2}}}{2}$
- C
$\frac{{2{K_1}{K_2}}}{{{K_1} + {K_2}}}$
- D
$\frac{{{K_1} + {K_2}}}{{2{K_1}{K_2}}}$
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