(adsbygoogle = window.adsbygoogle || []).push({}); A wall is composed of two materials. Material 1 has a thickness of 7.21 cm and a thermal conductivity of 0.1 while material 2 has a thickness of 6.57 cm and a conductivity of 1. If the temperature difference inside to outside is 25 Co and the wall has an area of 10 m2, what is the energy loss per second to the nearest watt?

My work:

Q1=kA (deltaT/L)t

=(.1)(10)(25/0.0721)t

=346.7t

Q2=kA (deltaT/L)t

=(1)(10)(25/0.0657)t

=3805.2

Qtotal = Q1+Q2

= 346+3805

=4151W

The answer is 318. Any help would be greatly appreciated.

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# Homework Help: Heat flow with two materials

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