1. A sphere of surface area 100 m and temperature 500 K radiates 0.2 MW. Calculate: a. The emissivity of the surface. b. The peak wavelength of radiation emitted. C. The intensity at a distance of 100m from the centre. d. The energy absorbed per second by a 2m disc with albedo 0.6 placed with it's plane perpendicular to the direction of the radiation. e. The temperature of the disc when it reaches equilibrium (emissivity of the disc = 1). P= eAoT A = 0.00289/T Page 11 1

1. A sphere of surface area 100 m and temperature 500 K radiates 0.2 MW. Calculate: a. The emissivity of the surface. b. The peak wavelength of radiation emitted. C. The intensity at a distance of 100m from the centre. d. The energy absorbed per second by a 2m disc with albedo 0.6 placed with it's plane perpendicular to the direction of the radiation. e. The temperature of the disc when it reaches equilibrium (emissivity of the disc = 1). P= eAoT A = 0.00289/T Page 11 1