The figure shows the cross section of a wall made of three layers. The thicknesses of the layers are L1, L2 =0.600 L1, and L3 = 0.400 L1. The thermal conductivities are k1, k2 = 0.820 k1, and k3 = 0.720 k1. The temperatures at the left and right sides of the wall are TH = 28 ?C and TC = -10 ?C, respectively. Thermal conduction is steady. (a) What is the temperature difference ?T2 across layer 2 (between the left and right sides of the layer)? If k2 were, instead, equal to 1.000 k1, (b) would the rate at which energy is conducted through the wall be greater than, less than, or the same as previously, and (c) what would be the value of ?T2?

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