Can you guys please explain to me planks hypothesis? This is what I know. But I need a better understanding: Planck’s hypothesis was designed to explain the problem of black-body radiation and the observed ‘ultraviolet catastrophe,’ not reconcilable with classical physics. Classical physics predicted (via laws of thermodynamics) that the radiation emitted by a black body was different to that observed in real life. Classical theory predicted as the wavelength of the black body radiation decreased, the radiance would increase to an infinite amount (could not be reconciled with laws of conservation of energy). Thus an explanation had to be found. Planck proposed a theory of quantum physics, which stated that all energy is quantised. As such, all the energy exchanged within the black body exists as packets. I need to know the mathematics behind Plank's Hypothesis, how did he come up with his explanation? Einstein extended the concept of quantised energy to light waves, reasoning that the energy from light waves may be treated as a stream of discontinuous quanta, called ‘photons’. This contribution to quantum theory was based upon Planck’s hypothesis on the quantisation of energy emitted from a black body. A photon is the smallest amount of radiation energy possible at a particular frequency. A photon cannot transfer part of its energy: it can only transfer all of its energy or none of it. The amount of energy carried by a photon is proportional to its frequency. The intensity of light is proportional to the number of photons. The energy possessed by a photon is proportional to its frequency (the shorter the wavelength - the higher the frequency - the greater the total energy). The energy of photons is given by: E=hf. So Plank's Hypothesis was limited to energy only, Einstein is the one who extended it to EMR?