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EF17xx
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Hi! I'm trying to understand a perfectly black body. So the definition I have found is that
a black body is one that absorbs radiation of ALL wavelengths and reflects NONE. Therefore it appears black at low temperatures. And when heated it emits radiation of all wavelengths making it appear very bright yellow orange.
So now I'm trying to understand HOW and WHY.
When atoms of a substance absorb energy for example in the form of radiation, the radiation must have an energy that corresponds to the energy required for an electron to move between its energy levels. Jump to a higher energy level. And if the atom receives energy from radiation of different wavelengths it will reflect the ones that do not have the corresponding energy. In the case of a perfect blackbody this is not the case. It absorbs ALL.
What I don't understand is that when the body is heated, it receives energy (temperature is a measure of kinetic energy of particles) so why would it emit radiation. since when it emits the electrons jump to a LOWER energy level?
Also what makes a black body a black body because wouldn't that mean it consists of all the diffrent elements in the world to be able to absorb energy of all wavelengths and each element has atoms with different energy levels which always have to correspond to the energy that is being targeted at them.And I'm just wondering if someone could give me feedback on my thinking and to what extent it is correct and whether there is any additional information that could help me understand.
a black body is one that absorbs radiation of ALL wavelengths and reflects NONE. Therefore it appears black at low temperatures. And when heated it emits radiation of all wavelengths making it appear very bright yellow orange.
So now I'm trying to understand HOW and WHY.
When atoms of a substance absorb energy for example in the form of radiation, the radiation must have an energy that corresponds to the energy required for an electron to move between its energy levels. Jump to a higher energy level. And if the atom receives energy from radiation of different wavelengths it will reflect the ones that do not have the corresponding energy. In the case of a perfect blackbody this is not the case. It absorbs ALL.
What I don't understand is that when the body is heated, it receives energy (temperature is a measure of kinetic energy of particles) so why would it emit radiation. since when it emits the electrons jump to a LOWER energy level?
Also what makes a black body a black body because wouldn't that mean it consists of all the diffrent elements in the world to be able to absorb energy of all wavelengths and each element has atoms with different energy levels which always have to correspond to the energy that is being targeted at them.And I'm just wondering if someone could give me feedback on my thinking and to what extent it is correct and whether there is any additional information that could help me understand.
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