what were the 2 postulates from plancks discovery?
planks postulates are that energy is absorbed and emitted in discrete packets called quanta with the energy E = hf discontinuously, and according the wavelength max = b/T, the temperature of a blackbody is inversely proportional to its max wavelength, that is the lower the wavelength the higher its temperature.
there's also bohrs postulates on electron orbits
1. electron orbits remain in a fixed position or orbital without the emission of EM radiation
2. electrons can move up and down these orbits according to the energy differences between these orbits (E =hf --> need a certain frequency of light/threshold frequency to be able to do so).
and Einsteins postulates on the photo electric effect which states that there is a certain threshold frequency which needs to be present in light incident on a surface for that surface to emit an electron form its surface known as the work function, and that the intensity of light increases the amount of electrons that are emitted as long as its above that frequency, also increasing frequency of light will maximise the kinetic energy of the emitted electrons. there's a formula specifically for Einsteins one so u don't need to memorise it