The spectral emissivity and spectral reflectivity of a diffuse surface are given below: 1.0 0.2 0.2 0.1 n1 1.40 3.0 A (um) 1.40 3.0 A (um) i- Determine the total emissive power of the surface (in W/m²) if the surface is at 2000 K.

A 0.6m diameter sphere is suspended in an enclosure.  The ball is kept at aconstant 200oC, while the enclosure is kept at 25oC. a) If the enclosure is opaque, how much radiation is emitted by the ball into the enclosure? b) If the enclosure is not opaque, it does not form a black body.  Let’s say the enclosure has a transmissivity of 0.6 and a reflectivity of 0.2.  How much thermal radiation is absorbed by the enclosure?

A spherical particle of diameter D = 10 mm is suspended by a thin wire within a cylindrical tube of inner diameter D2 length L = 0.5 m. = 30 mm anc A4 A2 D2 L. -A1 -A3 Determine the view factors F11, F12, F13, and F14 for S = 80 mm. The view factor between the sphere and the bottom end of the tube (a disk of radius r3) is F13 = 0.5 1 – (1 + R)-2 where R3 = r3/S. F11 = i F12 = i F13 = i F14 =

consider a 1m by 1m blackbody surface at ts = 300k. determine the blackbody emissive power. determine the total intensity. determine the radiosity. if the plane size is 100E-6m can you use the black body concept?