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### Question: Wave Model vs. Photon Model of Light

Posted: Thu Oct 01, 2015 2:25 pm
I know that the Photoelectric Effect shows that light can be thought of as tiny packets of energy in the form of photons because when the amplitude/intensity of the wavelengths of light (under the wave model) was increased, electrons were still not released from the metal surface. I just don't really understand how the experiment demonstrating the photoelectric effect shows how the wave model does not apply to that situation and why the photon model is a better way of looking at light.

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Thu Oct 01, 2015 3:05 pm
I understood it as the experiment involving the Photoelectric Effect indicated that it was the frequency of light that determined whether or not electrons were released, rather than the intensity. Therefore, it showed that light has both wave and particle properties, and in this case it was the particle (photon) aspect of light that released electrons. I'm unsure if I understood the question correctly, but hope this helps.

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Thu Oct 01, 2015 7:07 pm
I believe the wave model demonstrated that light had only contained wave properties. Therefore, it did not involve the idea of quanta. The photoelectric effect, like Neil said, proved that light has wave and particle properties. It showed that if light had only wave properties, then electrons should have ejected when the scientists increased the intensity of the light. Since this did not happen and the threshold energy varies depending on the metal, the photoelectric effect proved that light not only contains wave properties, it contains particle properties.

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Thu Oct 01, 2015 8:57 pm
In the classical wave theory, the total energy delivered by a wave is proportional to its amplitude squared which is also described as the intensity. So it was thought that to eject an electron, one simply has to deliver enough total energy (by cranking up the intensity). But it turns out that it's not the total energy that matters, but the energy PER PHOTON must pass a threshold and the only way to do this is to increase the frequency.

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Fri Oct 02, 2015 12:27 pm
I believe that the photon model of light showed that light has both wave and particle properties. Thus, this model shows that because it is specifically about the photon of light hitting the medal which emits an electron. I hope this helps!

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Sat Oct 03, 2015 5:01 pm
Just to recap the experiment, the observations from the experiment showed that
1. no electrons were ejected unless radiation has frequency above a certain threshold value characteristic of the metal
2. electrons were ejected immediately, however low the intensity of the radiation
3. kinetic energy of the ejected electrons increased linearly with the frequency of the incident radiation

If you were to say that only the wave model would explain the situation, the observations wouldn't support the model, as a certain amount of frequency (rather than amplitude of wave) was required to eject the electrons from the metal, and energy=planck's constant * frequency, which relates to the idea of having 'packets of energy' in the form of photons in light.

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Wed Oct 07, 2015 5:42 pm
Thank you all!! It's much clearer now, and I definitely have a better understanding. Thanks for the clarification.

### Re: Question: Wave Model vs. Photon Model of Light

Posted: Wed Dec 02, 2015 6:31 pm
If light acted as a wave in the photoelectric effect, then increasing the intensity would increase the amplitude and therefore cause electrons to be emitted. But none were. This shows that it does not act as a wave, but instead as a particle. The only way they could emit electrons was when they used a different light source with a higher frequency.