Concept explainers
To Calculate:The rate of heat
Answer to Problem 21P
The total thermal current is
The ratio of the heat that escapes through the door knob to the heat that escapes through the door is
The overall R-factor for the door is
Explanation of Solution
Given:
The thickness of the door =
The thermal conductivity of brass =
Formula used:
For thermal current
T is the temperature
Calculation:
The thermal current through the door is
The thermal current through the knob is
The total thermal current is
Assume that,
Considering the thickness of door and the length of the knob as same.
The heat escaped through the knob is divided with the heat escaped through the door.
As the door and the knob are parallel, the equivalent R-factor is,
R-factor of the knob is
R-factor of the door is
From equation (3)
The overall R-factor for the door is
Conclusion:
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Chapter 20 Solutions
Physics for Scientists and Engineers
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