Who came up with the Photoelectric effect? Einstein or Planck?

God came up with it....Eintsein did the math and got the prize.

It is not generally known that Albert Einstein did not get the Nobel Prize for Relativity. He received the 1921 prize in 1922 for work that he did between 1905 and 1911 on the Photoelectric Effect.

Max Planck had shown that each colour of light had its own energy. Planck made it possible to translate the colour into any desired units. So if we imagine the smallest-possible ray of light striking an electron, it would move that electron as if a voltage were moving that electron.

So on the fringe of infra-red one would expect about 1.7 volts, and the voltage rises throughout the visible band until it becomes about 3.2 on the fringe of ultra-violet.

The constant of proportionality that makes such calculations possible, h, became known as Planck`s Constant. It is proportional to the slope of the sloping line above.

Einstein discovered that every metal has its own "paste" (p) by which the electrons are held in place. You have to pay (p) the price (p) of liberating those electrons.

The alkali metals lithium Li, sodium Na, potassium K, and so on have the lowest voltages, generally about 2V. So if you have light on the fringe of ultraviolet, of 3.2eV, and a metal whose electrons are pasted in with 2V, the light will liberate electrons with an energy of 1.2V; the amount left over.

We speak of "eV", of electron-volts, because light does not have a voltage. The electron-volts are the voltage of the electrons after they were struck by that light.

The discovery that electrons are pasted into the atoms with different strengths of paste (p) led to a flurry of research to decipher the inner workings of atoms. After ten years, the Nobel Prize Committee had decided to award the prize to Einstein for discovering the Work Function, p.

Photoelectrics had arrived. It became possible by careful choice of work-function to create an Einstein photoelectric cell that would see in the dark. It became possible to record sound as a stripe of varying density or width on a film. Cinema audiences could listen to sound delivered by a photocell.

Plank discovered that energy exists in discreet amount and is credited with the foundation of Quantum Theory.

Einstein used the idea of quantized energy to demonstrate the photoelectric effect and show that light behaves like particles.

Both of them happens to be fooling around with it at the same time. I believe it was Max Planck that stumbles into it and start messing with it. Einstein, however, may have done an actual exprimentation on it. Don't qoute me on this though. you may have to do a little research on it yourself to learn more of who done what. Good enough, yes?

Planck, although Einstein beat him to the logistics of it.