Imperfect varieties of these entities have emissiv
Imperfect varieties of these entities have emissivities of less than one. One law governing the behavior of these objects performs poorly at long wavelengths, while another predicts infinite power at small wavelengths, leading to the ultraviolet catastrophe. Wien's Law and the Rayleigh-Jeans law describing these objects were replaced by a law in which energy was [*] quantized. The energy radiated per unit surface area by one of these objects is proportional to the fourth power of its temperature according to the Stefan-Boltzmann law. Their namesake spectrally-continuous radiation is described by Planck's law. For 10 points, name these objects that absorb all radiation falling on them.
Imperfect varieties of these entities have emissivities of less than one.
{black body} [or {black bodies}]