Question

In a furnace, the wall thickness is 60 cm and is 100 cm wide by 150 cm height, made of material with thermal conductivity 0.4 W/mK. The temperature inside and outside are 1000°C and 4°C, respectively. The thermal resistance is —————.

• A. 1 K/W
• B. 2 K/W
• C. 18 K/W
• D. 15 K/W

Hint:

Thermal resistance is inversely proportional to both conductivity and cross-sectional are(A)

Answer 1

The Correct Option is B

- The thermal resistance for conduction is given by \[ R_{th} = \frac{L}{k A} \] where \( L = 0.6 \, {m} \), \( k = 0.4 \, {W/mK} \), and \( A = 1.5 \times 1 \, {m}^2 \). \[ R_{th} = \frac{0.6}{0.4 \times 1.5} = 2 \, {K/W} \] Conclusion: The correct answer is option (B).