Bunuel wrote:
How quickly heat transfers through an insulating layer depends on that insulator's thermal resistance. If two insulators are used together, the inverse of the combined thermal resistance is sum of the reciprocals of each layer's thermal resistance. If the thermal resistances of two insulators are r and 2r, what is their combined resistance?
A. 2r^2
B. 3r
C. 1/(3r)
D. 2r/3
E. 3/(2r)
Project PS Butler
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Subscribe via RSS - RSSGiven: How quickly heat transfers through an insulating layer depends on that insulator's thermal resistance. If two insulators are used together, the inverse of the combined thermal resistance is sum of the reciprocals of each layer's thermal resistance.
Asked: If the thermal resistances of two insulators are r and 2r, what is their combined resistance?
1/R = 1/r + 1/2r = 3/2r
R = 2r/3
IMO D
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