From my understanding, the Photoelectric Effect knocks electrons off of some metal using photons. Since electrons are being thrown out of the metal, does this cause some kind of decay?
2 Answers
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(I am guessing that you by "decay" mean, "is the material loosing mass slowly". As the other answer suggests, decay is a word reserved for something else in physics.)
"Knocs electrons off" is in this sense quite a simplistic way to describe it. Rather see it like this:
- The photoelectric effect is when a photon (light) excites an electron. "Excites" means that it has more energy (a higher energy state), and in this case enough energy to move now (enough energy to reach the socalled conduction band). Moving electrons is current.
Just remember that this material from which the electrons are "ripped off" from - or rather excited in - is a part of a circuit. In an electric circuit the electrons moving away are as part of the current replaced by new electrons right away from further down the circuit.
Electrons are moving around the circuit at all points at all times if you have a steady current.
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$\begingroup$ You're describing a scenario similar to solar panels, correct? What if, let's say, a metal plate was floating in a vacuum without any way to complete any type of circuit. What would happen to the metal then? $\endgroup$– NoVaCommented May 27, 2015 at 21:56
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$\begingroup$ @Kosta Yes, the photoelectric effect is the soul cause in solarpanels. If the plate is a photoelectric material, then electrons will get excited as always. They will start moving in the same manner. But very quickly, electrons will pile up in one end creating a counter-electric field, which will stop the electron flow. Unless sparks start to fly or the material melts, or something like that, nothing more happens. That is why you have no steady current in an open circuit. $\endgroup$– SteevenCommented May 27, 2015 at 22:01
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$\begingroup$ thank you. That helped clear up a lot of questions I had about this. $\endgroup$– NoVaCommented May 28, 2015 at 14:43
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No decay within atoms is where the neutrons or protons change such as beta which is a neutron to proton. Removal of electrons doesn't alter the element or nucleus structure.
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$\begingroup$ Okay, let's assume that the vast majority of electrons have been knocked off of the metal, how does that affect the metal? Does it become positively charged? Does the metal break apart easier (on a macro scale)? How does the absence of electrons affect the metal? $\endgroup$– NoVaCommented May 27, 2015 at 21:45
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$\begingroup$ just seen this can answer your questions far better than i will physics.stackexchange.com/questions/134289/… $\endgroup$ Commented May 27, 2015 at 21:46
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$\begingroup$ crucially however your removing a conduction band electron which wouldn't affect the properties. Positively charging the metal would be a different process entirely. $\endgroup$ Commented May 27, 2015 at 21:52