A small disk \(4 \mathrm{~mm}\) in diameter is positioned at the center of an isothermal, hemispherical enclosure. The disk is diffuse and gray with an emissivity of 0.8 and is maintained at \(1000 \mathrm{~K}\). The hemispherical enclosure, maintained at \(300 \mathrm{~K}\), has a radius of \(100 \mathrm{~mm}\) and an emissivity of 0.85 .

Calculate the radiant power leaving an aperture of diameter \(2.5 \mathrm{~mm}\) located on the enclosure as shown.

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R=100 mm 45 Disk Aperture Hemispherical enclosure