Two infinitely long parallel disks are in a vacuum. Disk 1 is a blackbody maintained at 25 °C. Disk 2 is di ffuse and opaque and also maintained at 25 °C. The net radiation leaving disk 1 is than that leaving disk 2. disk 1 disk 2 greater than less than the same as not enough information

Calculate the energy associated with a radiation having wavelength 3000 Å. Give the answer in kcal mol-¹ and also in kJ mol-¹.

A 1 m diameter cylinder, 1 m long, is maintained at 800 K and has an emissivity of 0.65. Another cylinder, 2 m in diameter and 1 m long, encloses the first cylinder and is perfectly insulated. Both cylinders are placed in a large room maintained at 300 K. Calculate the heat lost by the inner cylinder.

31 For approximate calculations, the sun may be considered a black body, emitting radiation with a maximum intensity at λ = 0.5 microns (5000 Å). With this information, estimate (a) the surface temperature of the sun, and (b) the emitted heat flux at the sun's surface.