It is a good approximation of a grey body. Because the human eye cannot perceive colour at very low light intensities, a black body, viewed in the dark at the lowest just faintly visible temperature, subjectively appears grey (but only because the human eye is sensitive only to black and white at very low intensities – in reality, the frequency of the light in the visible range would still be red, although the intensity would be too low to discern as red), even though its objective physical spectrum peaks in the infrared range. A perfectly insulated enclosure that is in thermal equilibrium internally contains black-body radiation and will emit it through a hole made in its wall, provided the hole is small enough to have negligible effect upon the equilibrium.Ī black-body at room temperature appears black, as most of the energy it radiates is and cannot be perceived by the human eye. The thermal radiation spontaneously emitted by many ordinary objects can be approximated as black-body radiation. It has a specific spectrum and intensity that depends only on the body's temperature, which is assumed for the sake of calculations and theory to be uniform and constant. Black-body radiation is the within or surrounding a body in with its environment, or emitted by a (an opaque and non-reflective body). The color () of black-body radiation depends on the temperature of the black body the of such colors, shown here in, is known as the.
0 Comments
Leave a Reply. |