compare and contrast plank's hypothesis, photoelectic effect,?

Question

thx!

compare and contrast:

plank's hypothesis,

photoelectic effect,
and
blackbody radiation

Answer 1

In his hypothesis, Planck assumed that the energy in light waves came in multiples of hv (h is Planck's constant, v is the frequency of the wave). Planck proposed this quantization of energy had something to do with the way the light was emitted by the walls of the back body/cavity. This change light from being a continuous spectrum of energy to only existing at discrete energy levels and in the process resolved the 'back body catastrophe'.

Afterward, Einstein took it a step further in his explanation of the photoelectric effect. He said that all electromagnetic radiation came in these discrete energy 'packets' in multiples of hv. In this way light has a particle nature in addition to its wave nature, depending on how you observe it.