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samreen
- 25
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what is 'black radiation' ? or specifically, the meaning of the phrase "radiation in equilibrium with matter"...in the context of thermal radiation. clueless here :'(
Correct, the inside of an oven is a pretty good black bodynope. i mean black radiation. I am talking general here. we know from kirchhoffs work that any enclosure that is opaque to all kinds of radiation, will when maintained at any constant temperature, behave like an ideal black body, and emit radiation characteristic of that temperature, right?
image a piece of black material (eg soot covered metal) placed inside an oven, infrared radiation from the oven will hit the material, be absorbed and heat it up.what i don't follow is when the texts say that any speck of matter placed inside such an enclosure will attain equilibrium with the radiation filling the enclosure and the blacker it is, the faster this will happen. when it has, this speck starts emitting black radiation