Photoelectric Effect and light as a particle

In summary, the conversation discusses the question of whether light is a particle or a wave and the effects and evidence that support each theory. The discussion covers the photoelectric effect experiment, Thomas Young's Double Slit Experiment, the De Broglie Hypothesis and wavelength, and the concept of wave-particle duality. References and resources are also shared for further research on the topic.
  • #1
Cmertin
58
0
I have a question, why does light act like a particle during the Photoelectric Effect Experiment, but acts as a wave in Thomas Young's Double Slit Experiment? Does anyone have a good book that I could rent in the Library or find on Questia.com or find online that I could use to read up on this?
 
Physics news on Phys.org
  • #2
Do you mean why does the photoelectric effect show that light is a particle?
For the photon to eject an electron there must be enough energy in a single photon - you can't use lots and lots of lower energy ones.
This proves that photons are discrete.

The wave part is more interesting. Photons don't behave like waves - everything does! Even elephants defract through a slit. But the wavelength decreases with increasing momentum so it's only noticable with very low momentum particles such as massless photons or low mass particles like electrons
It's called the de Broglie wavelength
 
  • #3
Yes, I meant why the photoelectric effect shows that light is a particle? I have to write a 4,000 word paper on whether light is a particle or wave, and I have the "waviness" (DeBroglie Hypothesis/Wavelength). I need a work though that explains in greater detail about the photoelectric effect.
 
  • #4
Last edited by a moderator:
  • #6
Thanks for your guy's help, those look like good/solid references for my paper. And Phrack, I thank you personally because I was looking for that but couldn't find it.

I found a site on how to conduct a cheap $100 photoelectric experiment (with LED's) and my teacher has all the materials for Young's Double Slit Experiment. Right now I just have to make an outline and an annotated Bibliography (haven't done any of the labs yet) before school starts on Aug. 25.

Does anyone know what I could put in it? This is what I have so far (it's in no specific order and the sources that you guys gave me are not added yet because I have to go tutor):
Question that I have to answer: Is light a particle or wave and what effects it and why?

• Thomas Young’s Double Slit Experiment
o http://www.glenbrook.k12.il.us/gbssci/phys/Class/light/u12l3d.html

• Photoelectric Effect Experiment

• De Broglie Hypothesis
o De Broglie Wavelength
http://hyperphysics.phy-astr.gsu.edu/hbase/mod1.html

• Explination of Photoelectric Effect
o Why it acts as a particle
 Photons and threshold freqency
 “The photoelectric effect is the emission of photoelectrons from a clean metal surface due to incident light whose frequency is greater than a threshold frequency. The photoelectric effect supports the particle theory of light because it shows that the energy required to release electrons from a metal is totally dependent upon the frequency of the light, and not the intensity. Therefore, certain frequencies of light, no matter how intense, cannot cause an electron to be emitted from the surface of a metal”

• Wave-Particle Duality
o http://physics.about.com/od/lightoptics/a/waveparticle.htm

• Background Information
o http://physics.weber.edu/carroll/honors-time/duality.htm
 
Last edited by a moderator:
  • #7
I'd read your paper once you finish and referenced it on the physics forum. Though I'm not sure you are allowed, personally, to link to your own material per PF rules.
 

What is the photoelectric effect?

The photoelectric effect is the phenomenon where certain materials, when exposed to light, emit electrons. This was first observed by Heinrich Hertz in 1887 and was further explained by Albert Einstein in 1905.

What is the significance of the photoelectric effect?

The photoelectric effect provided evidence for the particle nature of light, which was previously thought to only behave as a wave. This led to the development of quantum mechanics and helped shape our understanding of the nature of light.

How does the photoelectric effect work?

When a photon of light hits a metal surface, it transfers its energy to an electron, giving it enough energy to escape the atom's surface. This results in a flow of electrons, known as an electric current.

What is the threshold frequency in the photoelectric effect?

The threshold frequency is the minimum frequency of light required to cause the photoelectric effect. Below this frequency, no electrons will be emitted, regardless of the intensity of the light.

How does the intensity of light affect the photoelectric effect?

The intensity of light determines the number of photons hitting the metal surface, which in turn affects the number of electrons emitted. However, it does not affect the energy of each individual electron, which is determined by the frequency of the light.

Similar threads

Replies
5
Views
647
Replies
5
Views
820
Replies
10
Views
2K
  • Quantum Physics
2
Replies
36
Views
1K
Replies
13
Views
1K
  • Quantum Physics
Replies
11
Views
1K
Replies
3
Views
1K
Replies
2
Views
1K
Replies
25
Views
2K
  • Introductory Physics Homework Help
2
Replies
35
Views
1K
Back
Top