Importance of light waves versus quantized photons


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Simone Seliger 1C
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Joined: Fri Sep 25, 2015 3:00 am

Importance of light waves versus quantized photons

Postby Simone Seliger 1C » Fri Oct 02, 2015 2:20 pm

Why is increasing the energy of light waves not enough to determine the emission of the electron from the metal in photoelectric effect?

Emma Edmond 3E
Posts: 29
Joined: Fri Sep 25, 2015 3:00 am

Re: Importance of light waves versus quantized photons

Postby Emma Edmond 3E » Fri Oct 02, 2015 2:33 pm

In order to have the threshold energy to eject the electron from the metal, the radiation from the light source must have a frequency about a certain threshold value that is characteristic of that particular metal. Therefore, if the energy of a photon is less than the energy required to remove an electron from the metal, then the electron will not be ejected (regardless of the intensity of the electromagnetic radiation). If you increase the energy per photon, then you will have an excess amount of energy that is not needed to eject the electrons, so that is released as kinetic energy. The kinetic energy increases linearly with the frequency of the radiation. Therefore, by just increasing the energy of the photons you are not actually increasing the amount of electrons ejected, just the amount of kinetic energy of the ejected electrons.

Simone Seliger 1C
Posts: 30
Joined: Fri Sep 25, 2015 3:00 am

Re: Importance of light waves versus quantized photons

Postby Simone Seliger 1C » Thu Oct 08, 2015 1:02 pm

Okay. But why not just change the type of light (i.e., blue to purple light for a higher frequency and therefore more energy) instead of using photons?

Again, I am just curious despite knowing that photons are the way to go when solving these types of problems.


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