A) 2890 W
B) 2830 W
C) 2800 W
D) 2822 W
Correct Answer: D
Solution :
The area of roof \[A=4\times 4=16\,{{m}^{2}}\] Thickness, \[x=10\text{ }cm=0.10\text{ }m\] The thermal resistance of the roof is \[R=\frac{x}{KA}=\frac{1}{1.26}\times \frac{0.10}{16}\] \[=4.96\times {{10}^{-3}}\,{}^\circ C{{W}^{-1}}\] \[\therefore \]Rate of heat flow (i.e. heat current) \[\frac{\Delta Q}{\Delta t}=\frac{{{T}_{1}}-{{T}_{2}}}{R}=\frac{46{}^\circ C-32{}^\circ C}{4.96\times {{10}^{-3}}\,{}^\circ C{{W}^{-1}}}\] \[\Rightarrow \] \[\frac{\Delta Q}{\Delta t}=2822\,W\]You need to login to perform this action.
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