Question 934: Thermodynamics & KTG

Question

The temperature difference bewtween two sides of metal plate, $$3 \mathrm{~cm}$$ thick is $$15^{\circ} \mathrm{C}$$. Heat is transmitted through plate at the rate of $$900 \mathrm{~kcal}$$ per minute per $$\mathrm{m}^2$$ at steady state. The thermal conductivity of metal is

Accepted Answer

$$\begin{aligned} & \frac{\mathrm{Q}}{\mathrm{tA}}=\frac{\mathrm{k} \Delta 	heta}{\mathrm{d}} \ & 	herefore \mathrm{k}=\frac{\mathrm{Q}}{\mathrm{tA}} \cdot \frac{\mathrm{d}}{\Delta 	heta} \ & \frac{\mathrm{Q}}{\mathrm{tA}}=900 \mathrm{~kcal} 	ext { per minute per } \mathrm{m}^2=\frac{900}{60}=15 \mathrm{~kcal} / \mathrm{sm}^2 \ & \mathrm{~d}=3 \mathrm{~cm}=3 	imes 10^{-2} \mathrm{~m}, \Delta 	heta=15^{\circ} \mathrm{C} \ & 	herefore \mathrm{k}=\frac{15 	imes 3 	imes 10^{-2}}{15}=3 	imes 10^{-2} \mathrm{kcal} / \mathrm{ms}^{\circ} \mathrm{C}\end{aligned}$$

Answer

$$1.8 	imes 10^{-2} \frac{\mathrm{kcal}}{\mathrm{ms}^{\circ} \mathrm{C}}$$

Answer

$$4.5 	imes 10^{-2} \frac{\mathrm{kcal}}{\mathrm{ms}^{\circ} \mathrm{C}}$$

Answer

$$3 	imes 10^{-2} \frac{\mathrm{kcal}}{\mathrm{ms}^{\circ} \mathrm{C}}$$

Answer

$$6 	imes 10^{-2} \frac{\mathrm{kcal}}{\mathrm{ms}^{\circ} \mathrm{C}}$$

Thermodynamics & KTG

The temperature difference bewtween two sides of metal plate, $3 \mathrm{~cm} thick is 15^{\circ} \mathrm{C}. Heat is transmitted through plate at the rate of 900 \mathrm{~kcal} per minute per \mathrm{m}^2$ at steady state. The thermal conductivity of metal is

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