The R-Value of an Insulating Material Is the Thickness of the Material

question 31

Multiple Choice

The R-value of an insulating material is the thickness of the material divided by its thermal conductivity.When an insulating material consists of three layers with R-values R₁,R₂ and R₃,the overall R-value of the insulation is given by

• A)R = R₁ + R₂ + R₃.
• B) .
• C) .
• D) .
• E) .