## Threshold Energy

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

Posts: 64
Joined: Fri Sep 28, 2018 12:27 am

### Threshold Energy

Can someone explain what threshold energy is and how it is relevant to today's lecture? Thank you.

Leela_Mohan3L
Posts: 44
Joined: Fri Sep 28, 2018 12:26 am

### Re: Threshold Energy

Threshold energy is the amount of energy required to remove an electron from an atom of a certain material. The electron will only be removed if the light source has enough energy to overcome this threshold energy.

Hope that helps!

Nicole Lee 4E
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am
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### Re: Threshold Energy

The threshold energy is the work required to remove an electron from a metal surface. The energy of the photon must be greater or equal to the threshold energy in order to remove an electron from the surface. E(photon) - Threshold Energy = Kinetic Energy of Electron

Rylee Nelsen 3A
Posts: 37
Joined: Fri Sep 28, 2018 12:22 am

### Re: Threshold Energy

The threshold energy is basically the minimum kinetic energy required to remove an electron. Also, the energy of photoelectrons emitted when light hits a metal depends on the frequency. When light with the right frequency is shone onto a metal surface, electrons are emitted from the surface.

leediane0916
Posts: 31
Joined: Fri Sep 28, 2018 12:29 am

### Re: Threshold Energy

Threshold Energy is the minimum required amount of E that a photon should contain for the photon to release an electron from the metal surface. The threshold E + E of the electron is equal to the E of the photon. As explained in the lecture, if the electron's E is 0, that means that the photon's E was equal to the threshold E, leaving no excess E (kinetic E)