if KE is 0 how can the electron be ejected?

Moderators: Chem_Mod, Chem_Admin

kendal mccarthy
Posts: 109
Joined: Wed Nov 14, 2018 12:22 am

if KE is 0 how can the electron be ejected?

Postby kendal mccarthy » Sun Oct 20, 2019 2:01 pm

How is the electron ejected if the energy of the photon is equal to that of the work function, meaning it has no KE? Because wouldn't it not be able to move if it has 0 KE?

Noah Canio 3C
Posts: 55
Joined: Wed Sep 18, 2019 12:20 am

Re: if KE is 0 how can the electron be ejected?

Postby Noah Canio 3C » Sun Oct 20, 2019 2:44 pm

If I remember correctly, Dr. Lavelle explained that the detector used to measure the kinetic energy of the ejected electron has a slight positive charge. This means that even if the electron is hit with an energy equal to the threshold needed (the work function), the electron will move slightly away. I don't particularly remember the minute details behind this, so if anyone can correct me if I'm wrong, then that would be greatly appreciated.

Bryce Ramirez 1J
Posts: 120
Joined: Sat Aug 24, 2019 12:16 am

Re: if KE is 0 how can the electron be ejected?

Postby Bryce Ramirez 1J » Sun Oct 20, 2019 3:26 pm

For an electron to be ejected, the work function just has to be equal to the to the amount of energy that was used when being put on the metal. I still think that there will be a slight positive charge, but it would be negligible to calculate it. For the formula, KE would equal 0 and you would be left with E = work function, which could be simplified to h * v = work function.

Jessa Maheras 4F
Posts: 121
Joined: Fri Aug 02, 2019 12:16 am

Re: if KE is 0 how can the electron be ejected?

Postby Jessa Maheras 4F » Sun Oct 20, 2019 11:08 pm

I agree with the above two responses - I believe that the word "ejected" simply means liberated from the atom. The slightly charged detector can account for the additional movement.

Adelpha Chan 1B
Posts: 58
Joined: Thu Jul 25, 2019 12:15 am

Re: if KE is 0 how can the electron be ejected?

Postby Adelpha Chan 1B » Tue Oct 22, 2019 3:14 pm

kendal mccarthy wrote:How is the electron ejected if the energy of the photon is equal to that of the work function, meaning it has no KE? Because wouldn't it not be able to move if it has 0 KE?


If there is 0 KE, it means that there was just enough energy for the electron to escape the surface of the solid metal. 0 KE refers to the fact that the electron is not driven outward with any additional kinetic energy but simply liberated from the metal.


Return to “Photoelectric Effect”

Who is online

Users browsing this forum: No registered users and 1 guest