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### Conditions that allow electron to be ejected from metal surface

Posted: Sun Oct 21, 2018 7:12 pm
Just to clarify, an electron can be ejected from a metal surface if the energy of the photon is greater than the energy required to remove the electron or if the energy of the photon is equal to the energy required to remove the electron?

### Re: Come nditions that allow electron to be ejected from metal surface

Posted: Sun Oct 21, 2018 7:13 pm
Yes, the energy of the photon just has to be equal to or greater than the work function of that specific metal to eject an electron.

### Re: Come nditions that allow electron to be ejected from metal surface

Posted: Sun Oct 21, 2018 7:15 pm
Yes. Both are true. Just bear in mind that if the energy of the photon is higher than the energy required to remove the electron, the remaining energy will present as kinetic energy of the ejected electron; the energy is conserved.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Sun Oct 21, 2018 7:18 pm
It has to be greater otherwise the metal just absorbs the energy and the electron will not be ejected. If the light energy equals the work function then the electron is ionized but it cannot be ejected from the metal because it has no kinetic energy.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Sun Oct 21, 2018 8:59 pm
It is also important to keep in mind the kinetic energy of the ejected electron increases linearly with the frequency of the radiation.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Sun Oct 21, 2018 9:33 pm
Remember that Ephoton = WorkFunction + KEejectede-. If Ephoton is less than the work function, the kinetic energy of the electron would be negative, and the electron would not be ejected.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Wed Oct 24, 2018 12:10 pm
There needs to be enough energy to eject an electron and give it kinetic energy once ejected. This is obtained when a photon has enough energy and the light has surpassed the threshold frequency.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Thu Oct 25, 2018 10:03 pm
Yes! In both situations the electron can be ejected, just to add on, the difference is that the ejected electron will have different kinetic energies.
When the energy of the photon is greater than the energy required to remove the electron, kinetic energy of the ejected electron will be larger than zero.
When the energy of the photon is equal to the energy required to remove the electron, the ejected electron will have no kinetic energy.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Thu Oct 25, 2018 11:18 pm
Will the work function of the metal be given when doing problems?

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Thu Oct 25, 2018 11:32 pm
Energy of the photon must be greater than or equal to the energy of an electron.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Fri Oct 26, 2018 12:24 am
correct. the energy of the photon must be greater than or equal to the work function of the specific metal (the minimum amount of energy needed to eject an e-) in order to eject an e-. if the energy of the photon is less than the work function of the metal, no e- will be ejected. if the energy of the photon is greater than the work function of the metal, then the remaining energy will be given off as kinetic energy of the ejected e-.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Sat Oct 27, 2018 10:50 am
Correct. If the energy of the photon is equal to the threshold energy (minimum energy required to release an electron) of the electron, then the electron is released with zero kinetic energy. If the energy of the photon is greater than the threshold energy, then the electron is released with positive kinetic energy. The electron will not be released if the energy of the photon is less than the threshold energy. The equation is: energy of photon = threshold energy + kinetic energy.

### Re: Conditions that allow electron to be ejected from metal surface

Posted: Sun Nov 04, 2018 5:03 pm
Basically. If the energy of the photon/light has greater energy than the threshold energy, then energy will be conserved and appear in the form of ejected electron's kinetic energy. If the energy of photon is equal to the threshold energy, it is a break even, and the kinetic energy of ejected electron would be zero. From that, since the electron obviously isn't losing mass to zero, the velocity must be zero so therefore the electron isn't moved at all.