Confused conceptually with photoelectric effect

LeannaPhan14BDis1D
Posts: 57
Joined: Fri Sep 28, 2018 12:16 am

Confused conceptually with photoelectric effect

I do not understand when Lavelle spoke on the length of the wavelength and how it ejects electrons. Please advice since the reading makes it only slightly less confusing. I get how the shorter the wavelength is it will eject more electrons, but I do not understand how. Thank you.

Chem_Mod
Posts: 18193
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 429 times

Re: Confused conceptually with photoelectric effect

The photoelectric effect refers to the emission of electrons when photons of light shine on a metal surface. Essentially, photons of light transfer the energy they carry to electrons they contact, and depending on how much energy is transferred, the electrons can absorb the energy, be emitted, and leave the metal the light was shown on. The minimum energy required to emit an electron from a metal refers to the metal's work function, or $\phi$. If the energy of a photon that contacts an electron happens to be lower than the metal's work function, then the electron will not be released. If the energy of a photon that contacts an electron happens to equal the metal's work function, then the electron will be released, but have no kinetic energy. If the energy of a photon that contacts an electron happens to exceed this work function, then the electron will be released and have kinetic energy. Based on the concepts here, it makes sense that the equation is as follows: Ephoton of light = $\phi$ + KEelectron emitted.

melodyzaki2E
Posts: 61
Joined: Fri Sep 28, 2018 12:18 am

Re: Confused conceptually with photoelectric effect

I think he was just trying to get the fact that the length of the wavelength is inversely related to the frequency of the photons, so long wavelengths didn't have enough energy to allow electrons to escape the metal but short wavelengths had high frequency so they were able to excite the electrons in the metal enough to allow them to escape. I don't know if that totally makes sense or if that was what you were confused about but hope it helped.

Douglas Nguyen 2J
Posts: 71
Joined: Fri Sep 28, 2018 12:15 am

Re: Confused conceptually with photoelectric effect

For the photoelectric effect, a shorter wavelength means a higher frequency. Higher frequency equates to a greater amount of energy in the photon, and thus, an electron is ejected because sufficient energy was provided. E=hv