Answer
1 mm
Work Step by Step
Calculate the rate of heat flow using equation 14–5.
$$\frac{Q}{t}=kA\frac{T_1-T_2}{\mathcal{l}}$$
$$150W=(\frac{0.2J}{s \cdot m \cdot C^{\circ}})(1.5m^2)\frac{0.5C^{\circ}}{\mathcal{l}}$$
Solve for a distance of 1 mm.