A 4-cm-diameter cylindrical enclosure of black surfaces, as shown in the accompanying sketch, has a 2-cm hole

Question:

A 4-cm-diameter cylindrical enclosure of black surfaces, as shown in the accompanying sketch, has a 2-cm hole in the top cover. Assuming the walls of the enclosure are at the same temperature, determine the percentage of the total radiation emitted from the walls which will escape through the hole in the cover.GIVENCylindrical enclosure of black surfaces shown aboveCylinder diameter (D) = 4 cm = 0.04 mDiameter of hole in top (Dh) = 2 cm = 0.02 mASSUMPTIONSThe walls of the enclosure are at the sametemperature