A copper rod 2 m long has a circular cross-s | vedclass

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(D) The thermal resistance $R$ of a rod is given by the formula:$R = \frac{l}{KA}$where $l$ is the length of the rod,$K$ is the thermal conductivity,a

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$15$

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(D) The thermal resistance $R$ of a rod is given by the formula:$R = \frac{l}{KA}$where $l$ is the length of the rod,$K$ is the thermal conductivity,and $A$ is the cross-sectional area.Given:Length $l = 2 \ m$Radius $r = 1 \ cm = 10^{-2} \ m$Thermal conductivity $K = 401 \ W/m-K$Cross-sectional area $A = \pi r^2 = 3.14 	imes (10^{-2})^2 = 3.14 	imes 10^{-4} \ m^2$Substituting the values into the formula:$R = \frac{2}{401 	imes 3.14 	imes 10^{-4}}$$R = \frac{2}{0.125914} \approx 15.88 \ K/W$Rounding to one decimal place,we get $R \approx 15.9 \ K/W$.

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