|MadSci Network: Physics|
1. Will a body emit infrared radiation if it's surrounding environment is at a higher temperature? Of course, all dense objects (a.k.a. bloackbodies, or at least good approximations to them) at temperatures higher than absolute zero will radiate infrared radiation (and other kinds too, depending on the temperature). However, remember, that good blackbodies not only emit radiation, they absorb it too. You are describing a situation here where the rate of energy absorption from the hotter environment will be higher than the rate of energy emission by the object. 2. Is radiant heat absorption only absorbed by free(unbound) electrons within a body? No, there are all sorts of ways energy can be taken up into an object, including in the form of vibrational energy in molecules or in a crystal lattice, rotational energy in molecules, and so forth. Energy can be absorbed into a body by many means. 3. Can bound electron photon absorption be converted to heat if the photon's energy is less than the ionization energy for that bound electron? If a photon has less energy than necessary for the electron in your atom/molecule to be ionized, there are two possible outcomes of the interaction between that photon and the atom/molecule. If the energy of the photon EXACTLY corresponds to an energy difference between electron orbital levels in the atom/molecule, the photon can be absorbed and the electron can jump up to a new orbital. The other possibility, the photon energy doesn't correspond to the energy difference between orbitals and the photon passes through the atom/molecule. However, that photon's energy can be converted into heat by other methods of converting its energy into heat including absorption of the photon into vibrational energy in the crystal lattice or an individual molecule or absorption by a free electron in the body. Note that these are not the only ways to have that photon's energy converted into heat, just some possibilties.
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