GATE 2024 CH – Question 34
The opposite faces of a metal slab of thickness 5 cm and thermal conductivity 400 W m$^{-1}$ °C$^{-1}$ are maintained at 500 °C and 200 °C. The area of each face is 0.02 m$^2$. Assume that the heat transfer is steady and occurs only in the direction perpendicular to the faces. The magnitude of the heat transfer rate, in kW, rounded off to the nearest integer, is _______
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Correct answer: 48
Explanation
By Fourier's law, $Q = \frac{kA\Delta T}{L} = \frac{400 \times 0.02 \times 300}{0.05} = 48000$ W $= 48$ kW.