Question

Two plates of same thickness, of coefficients of thermal conductivity K₁ and K₂ and areas of cross-section A₁ and A₂, are connected as shown ; the common coefficient of thermal conductivity K will be –

• A. K₁A₁ + K₂A₂
• B. $\frac{K_{1}A_{1} + K_{2}A_{2}}{A_{1} + A_{2}}$
• C. $\frac{K_{1}A_{2} + K_{2}A_{1}}{A_{1} + A_{2}}$
• D. $\frac{K_{1}A_{1}}{K_{2}A_{2}}$

Answer 1

Answer: (B)

$\frac{K_{1}A_{1} + K_{2}A_{2}}{A_{1} + A_{2}}$

Answer 2

K_P = $\frac{K_{1}A_{1} + K_{2}A_{2}}{K_{1} + K_{2}}$