A Slab of Concrete and an Insulating Board Are in Thermal

question 19

Multiple Choice

A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68°F and 50°F. Determine the rate of heat transfer (in BTU/ft2⋅h) if the R values are 1.93 and 8.7 ft2⋅°F⋅h/BTU, respectively.

• A)9.7
• B)2.5
• C)5.3
• D)1.7
• E)28

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