Threshold Energy

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MaryBanh_2K
Posts: 101
Joined: Wed Sep 18, 2019 12:21 am

Threshold Energy

Postby MaryBanh_2K » Fri Oct 18, 2019 3:42 pm

What happens if the energy of light matches the threshold energy level? What would happen to the electron(s) on the metal surface?

BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Re: Threshold Energy

Postby BNgo_2L » Fri Oct 18, 2019 3:44 pm

If the energy of the light equals the wave function (threshold), electrons will still be emitted, but there wouldn't be any excess energy (kinetic energy).

Gabriella Bates 2L
Posts: 113
Joined: Thu Jul 11, 2019 12:15 am

Re: Threshold Energy

Postby Gabriella Bates 2L » Fri Oct 18, 2019 3:50 pm

If the energy of the light matches the threshold energy, then electrons will be emitted from the surface. If the energy of light is greater than the threshold energy, then the electrons emitted will have increasing kinetic energy.

Kimme Chun 1I
Posts: 22
Joined: Sat Sep 07, 2019 12:17 am
Been upvoted: 1 time

Re: Threshold Energy

Postby Kimme Chun 1I » Sun Oct 20, 2019 8:36 pm

The electrons will be emitted but KE will equal 0.

Eesha Sohail 1D
Posts: 100
Joined: Sat Aug 17, 2019 12:16 am

Re: Threshold Energy

Postby Eesha Sohail 1D » Sun Oct 20, 2019 8:39 pm

Can something still be emitted with zero KE? It seems as though that would cause it to not move at all, and therefore not break free of the metal surface. However, it's possible I'm ascribing expectations of regular matter to the quantum level where they don't really apply.

Ashley Fang 2G
Posts: 102
Joined: Fri Aug 30, 2019 12:17 am

Re: Threshold Energy

Postby Ashley Fang 2G » Mon Oct 21, 2019 12:15 am

I think that "ejected" just means that the electron is released from the atom. The detector that is used to measure the KE of the ejected electron has a slightly positive charge, thus causing it to move.

Tiffany Dong_4e
Posts: 51
Joined: Wed Sep 11, 2019 12:17 am

Re: Threshold Energy

Postby Tiffany Dong_4e » Mon Oct 21, 2019 2:04 am

I'm also confused how an electron is "ejected" with no kinetic energy. Could someone clarify further?

AlyshaP_2B
Posts: 112
Joined: Wed Sep 18, 2019 12:19 am

Re: Threshold Energy

Postby AlyshaP_2B » Mon Oct 21, 2019 10:04 am

I believe that saying there is 0 KE means that after the electron has been ejected, there is no excess energy leftover that would be considered Kinetic Energy. When the energies match up, all of it is used to eject the electron so there will be 0 KE.


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