Respuesta :
Explanation:
The given data for case (1) is as follows.
h = 20 cm = 0.2 m
Assuming that a rectangular slab is placed above the pipe and we will calculate the heat transfer as follows.
Q = [tex]kA \frac{\Delta T}{L}[/tex]
where, A = area
L = length
k = thermal conductivity = 0.8 W/m
[tex]\Delta T[/tex] = change in temperature.
Therefore, putting the given values into the above formula as follows.
Q = [tex]kA \frac{\Delta T}{L}[/tex]
= [tex]0.8 W/m \times (4 m \times 0.15 m) \frac{75 - 5}{0.2}[/tex]
= 168 W
For case (2), h = 180 cm = 1.8 m
Therefore, heat lost will be calculated as follows.
Q = [tex]kA \frac{\Delta T}{L}[/tex]
= [tex]0.8 W/m \times (4 m \times 0.15 m) \frac{75 - 5}{1.8}[/tex]
= 18.67 W
Thus, we can conclude that 18.67 W heat lost if the pipe was buried at a depth of 180 cm.
