Question 99 of 126

Two identical metal wires of thermal conductivities ${K}_{1}$ and ${K}_{2}$ respectively are connected in series. The effective thermal conductivity of the combination is:

A$\dfrac{2{K}_{1}{K}_{2}}{{K}_{1}+{K}_{2}}$B$\dfrac{{K}_{1}+{K}_{2}}{2{K}_{1}{K}_{2}}$C$\dfrac{{K}_{1}+{K}_{2}}{{K}_{1}{K}_{2}}$D$\dfrac{{K}_{1}{K}_{2}}{{K}_{1}+{K}_{2}}$

Show answer and solution▾

Answer: (A) $\dfrac{2{K}_{1}{K}_{2}}{{K}_{1}+{K}_{2}}$

${R}_{eff}=\dfrac{l}{{K}_{1}A}+\dfrac{l}{{K}_{2}A}=\dfrac{2l}{{K}_{eq}A}$
${K}_{eq}=\dfrac{2{K}_{1}{K}_{2}}{{K}_{1}+{K}_{2}}$

JEE Main Physics practice question on Thermal Properties of Matter (Conduction), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.