【Daily Question】Theoretical Foundation 2020.12.16

This post was last edited by Huagong Student on 2020-12-16 08:35; the correct answer is A. Option A is correct. The surfaces of solar collectors or solar cookers are often made black primarily to increase their absorption rate; for most solid surfaces, this can be approximated as a gray diffuse body with α=ε ； Option B is incorrect; the highest emissivity in solar radiation is concentrated in the range of 0.2–3 μm, while the wavelength range of visible light is generally between 0.36 μm and 0.76 μm. Option C is incorrect; the absorption ratio of a black surface in the visible light range is close to 1, whereas its absorption ratio in the infrared range is close to 0 ； Option D is incorrect; radiative heat transfer refers to the net amount of heat exchanged. The surface is made black primarily to increase its absorptivity, thereby reducing the amount of radiation emitted.

This post was last edited by Huagong Student on 2020-12-16 08:35; the correct answer is A. Option A is correct. The surfaces of solar collectors or solar cookers are often made black primarily to increase their absorption rate; for most solid surfaces, this can be approximated as a gray diffuse body with α=ε ； Option B is incorrect; the highest emissivity in solar radiation is concentrated in the range of 0.2–3 μm, while the wavelength range of visible light is generally between 0.36 μm and 0.76 μm. Option C is incorrect; the absorption ratio of a black surface in the visible light range is close to 1, whereas its absorption ratio in the infrared range is close to 0 ； Option D is incorrect; radiative heat transfer refers to the net amount of heat exchanged. The surface is made black primarily to increase its absorptivity, thereby reducing the amount of radiation emitted.