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A black body, by definition, is an object which absorbs all radiation that fall on it. Since it does not reflect any light, it appears black. |
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In a laboratory, one could approximate a blackbody by a cavity with highly polished walls. If the walls of the cavity has a small hole, any radiation that enters through the hole gets trapped in the cavity. Stars may also be approximated as black bodies as any radiation directed at them gets absorbed. |
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A black body is also a perfect emitter of radiation. It can emit at all wavelengths. However, the radiation from a black body is observed to obey the following two laws : |
