## Photoelectric Effect as Proof of Particle Qualities of Light

Ashley Davis 1I
Posts: 57
Joined: Fri Sep 29, 2017 7:04 am

### Photoelectric Effect as Proof of Particle Qualities of Light

I get that the photoelectric effect proves light is a particle, but how exactly does it prove that? Like how does it prove that it is a particle?

manasa933
Posts: 72
Joined: Fri Sep 29, 2017 7:04 am

### Re: Photoelectric Effect as Proof of Particle Qualities of Light

A photon is causing the ejection of an electron which is a particle and hence, proving the particle nature of light.

K Stefanescu 2I
Posts: 68
Joined: Fri Sep 29, 2017 7:04 am

### Re: Photoelectric Effect as Proof of Particle Qualities of Light

Electrons will not be emitted from the metal unless EACH photon of light has sufficient energy. This was proven by the fact that simply increasing the intensity of a light source did not result in more electrons being emitted.

If light had been acting as a wave, increasing the intensity (and therefore the wave's amplitude) should have increased its overall energy, resulting in more electrons being emitted.

Since that did not occur, light must have been acting as a particle. Thus, in accordance with the particle model, increasing the intensity of the light simply increased the number of photons being emitted, but did not increase their individual energies.

Once the frequency of the light (v) was increased (and thus the wavelength decreased, because v is proportional to (1/wavelength)), more electrons were emitted. This gave us the equation of E=hv, or energy per photon, because increasing the frequency increased the energy of EACH particle of light, allowing electrons to be emitted. So, as light fit with this model best, in the photoelectric effect, light was acting as a particle.

snehabhargava
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am

### Re: Photoelectric Effect as Proof of Particle Qualities of Light

It is proved by the fact that when you increase the intensity, there is no change. That means that it is dependent on the individual particle and not on the wave as a whole.