Heat and Mass Transfer in Food Processing

A food processing oven wall is maintained with an inner surface at $T_1 = 200^\circ\text{C}$ and outer surface at $T_2 = 50^\circ\text{C}$ ($\Delta T = 150^\circ\text{C}$). The insulation has thermal conductivity $k = 0.05\text{ W/(m}\cdot\text{K)}$ and thickness $L = 0.1\text{ m}$. Heat flux $q'' = k \frac{\Delta T}{L} = 0.05 \times \frac{150}{0.1}$ in $\text{W/m}^2$ is: