What would extreme radiation do to the body?

What is a black body?what is black body radiation?

• I'm quiet confused with the definition of a black body?it absorbs all wavelength of EM radiation,not reflects but how emits all wave length EM,i thought it only emits thermal radiation.under what condition emits?.how stars are approximate black bodies?,how it laid the foundation of Quantum mechanics.

• Answer:

  A black body is a body that absorbs electromagnetic radiation of ALL wavelengths (at least a perfect black body does). It can transfer it into thermal energy which would explain why objects, that are painted or coloured black heat up faster and stronger when exposed to the sun (e.g. wearing a black sweater in summer, of course this is only an approximation). Why stars are approximate black bodies I cannot say but it laid the foundation of Quantum Mechanics in the following way: There is a so called Rayleigh-Jeans equation which states that a black body will emit infinite thermal energy. That, of course, is nonsense. Max Planck was also troubled by that and, as a last resort, he introduced a constant which states that energy is discrete (as it is in Quantum Mechanics) and he used that to derive Planck's law which makes correct predictions about the emission of energy of a black body.