## photoelectric effect module help!!

$c=\lambda v$

sabrina ghalambor 2J
Posts: 92
Joined: Wed Sep 30, 2020 9:35 pm

### photoelectric effect module help!!

has anyone found the answer to this question from the photoelectric effect module? if you did can you explain it please? thank you in advance!!!

21. What was the surprising outcome of the initial photoelectric experiments?

A. If electrons were ejected decreasing the light intensity resulted in no ejected electrons.

B. If electrons were ejected increasing the light intensity resulted in no ejected electrons.

C. If no electrons were ejected decreasing the light intensity resulted in ejected electrons.

D. If no electrons were ejected increasing the light intensity still resulted in no ejected electrons.

Jasmin Kumar 1G
Posts: 96
Joined: Wed Sep 30, 2020 9:46 pm

### Re: photoelectric effect module help!!

The answer for this is D. When they first did the experiment, no electrons were being ejected from the metal surface, so they increased the intensity of the light, and still there were no electrons being ejected. This is what made them change the frequency of the light to UV light, so that finally electrons would start to be ejected from the metal surface. The long wavelength of visible light didn't have a high enough frequency, so that is why they changed the light to UV light.

Andrew Wang 1C
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Joined: Wed Sep 30, 2020 10:11 pm
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### Re: photoelectric effect module help!!

The answer should be D. The photoelectric effect is one of the experiments that shows the particle properties of a photon. If photons acted only like waves, then increasing the intensity (amplitude) should result in ejected electrons (ike a wave at the beach, the higher it is, the stronger it is). However, since photons are acting like particles in this experiment, increasing the intensity would only increase the number of photons, none of which have enough energy to eject electrons.

Alexa Pham 1D
Posts: 69
Joined: Wed Sep 30, 2020 10:03 pm

### Re: photoelectric effect module help!!

D is the answer. The unexpected outcome of the photoelectric effect experiment was that increasing light intensity does not mean more electrons will be ejected from the metal. This led scientists to realize that light has properties of particles too! If light only followed the wave model, increasing light intensity (which means higher wave amplitude) SHOULD have more energy to eject an electron. However, experimentally, this was not the case.