The emitted intensity from a non-conducting material may be approximated as follows:

\[\begin{array}{ll}I_{e}=I_{n} & 0 \leq \theta \leq \pi / 3 \\I_{e}=I_{n}\left(3-\frac{6 \theta}{\pi}\right) & \pi / 3<\theta \leq \pi / 2\end{array}\]

where \(I_{n}=500 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{sr}\). Determine the total emissive power of the surface. Compare the emissive power to that of a diffuse surface with intensity \(I_{n}\).