$3\mathrm{.}2$ A particular dielectric material has a refractive index of $n=1\mathrm{.}346.$ For a smooth radiating

surface, estimate:

$($a$)$ the hemispherical emissivity of the material for emission into air.

$($b$)$ the directional emissivity at $=60$ into air.

$($c$)$ the directional$-$hemispherical reflectivity in air for both components of polarized

reflectivity. Plot both components for $n=1\mathrm{.}346$ on a graph similar to Figure $3\mathrm{.}5.$ Let $$

be the angle of incidence.

Answers: $($a$)0\mathrm{.}9315$ ; $($b$)0\mathrm{.}9379.$