Threshold Energy  [ENDORSED]

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Priscilla Okaiteye
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Threshold Energy

Postby Priscilla Okaiteye » Sun Apr 15, 2018 7:31 pm

I know this was covered in lecture but I'm still a bit confused. What exactly is the threshold energy and how does it relate to quantum equations?

Vivian Gonzalez 1A
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Re: Threshold Energy  [ENDORSED]

Postby Vivian Gonzalez 1A » Sun Apr 15, 2018 7:42 pm

Threshold energy is the amount of energy needed to eject an electron from a metal.

Neha Divi 1K
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Re: Threshold Energy

Postby Neha Divi 1K » Sun Apr 15, 2018 8:58 pm

To add on, the photoelectric effect is the idea that there is an ejection of electrons from a metal when its surface is exposed to ultraviolet radiation. Furthermore, no electrons are ejected unless the radiation has a frequency above a certain threshold that is characteristic of a metal.

Jada Larson 1F
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Re: Threshold Energy

Postby Jada Larson 1F » Sun Apr 15, 2018 10:13 pm

The equation related to threshold energy is:
Ephoton - Erequired to eject electron = Eexcess

Ephoton=hv. [*]h = 6.626 x 10-34 Js and [*]the v is frequency
Erequired to eject electron is called the threshold energy or the work function, and it is represented by the symbol ϕ.
Eexcess equals EK = (1/2)mv2. [*]note: the v is for velocity, not frequency

Cameron Smith 1I
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Re: Threshold Energy

Postby Cameron Smith 1I » Sun Apr 15, 2018 10:20 pm

What occurs to the kinetic energy that is the excess when the energy of the photon is greater than the threshold energy?

Alma Flores 1D
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Re: Threshold Energy

Postby Alma Flores 1D » Sun Apr 15, 2018 10:37 pm

In Friday's lecture, Dr. Lavelle mentioned that the energy of of the photon is equal to the sum of the threshold energy and the kinetic energy.

Sonia Aronson 1B
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Re: Threshold Energy

Postby Sonia Aronson 1B » Sun Apr 15, 2018 11:21 pm

The threshold energy is the minimum amount of energy required to move an electron from the surface of a metal.

Isobel Tweedt 1E
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Re: Threshold Energy

Postby Isobel Tweedt 1E » Mon Apr 16, 2018 2:08 pm

How does this relate to the concept of darkness versus lightness? Does the release of electrons result in our viewing of light and the color spectrum?

004985802
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Joined: Fri Feb 02, 2018 3:00 am

Re: Threshold Energy

Postby 004985802 » Thu Apr 19, 2018 8:10 pm

it is the energy required to move an electron from one state (energy level) to the next. If the input energy is less than threshold, the electron will remain at the same state (energy level).

breannasung_1K
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Re: Threshold Energy

Postby breannasung_1K » Fri Apr 20, 2018 3:42 am

Threshold energy is the amount of energy needed to remove an electron from the metal.

AnnaYan_1l
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Re: Threshold Energy

Postby AnnaYan_1l » Fri Apr 20, 2018 11:12 am

Cameron Smith 1I wrote:What occurs to the kinetic energy that is the excess when the energy of the photon is greater than the threshold energy?

I believe that in the photoelectric experiment, this kinetic energy is detected by a detector which shows the excess energy of the photon that surpassed the threshold energy (since kinetic energy = energy of the photon - threshold energy (also known as work function)).

NabilaNizam-1K
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Re: Threshold Energy

Postby NabilaNizam-1K » Fri Apr 20, 2018 1:37 pm

What affects the threshold energy of a photon?

Caroline Crotty 1D
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Re: Threshold Energy

Postby Caroline Crotty 1D » Fri Apr 20, 2018 2:38 pm

A threshold energy is specifically effected by what metal you are attempting to eject an electron from. Think of threshold energy almost as ionization energy, each metal will have its own specific threshold energy to have a single electron ejected.


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