Work Function

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Melissa Villanueva1K
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Joined: Wed Nov 15, 2017 3:01 am

Work Function

Postby Melissa Villanueva1K » Thu Oct 25, 2018 7:05 pm

How would we solve for the work function? Like what type of information would be given to use in order to find the work function and how would we use the given. Thanks!

Tarika Gujral 1K
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Joined: Fri Sep 28, 2018 12:27 am

Re: Work Function

Postby Tarika Gujral 1K » Thu Oct 25, 2018 7:42 pm

It depends on information given.
If given kinetic energy and energy/wavelength/frequency of incoming light, you can just subtract the energy of the incoming light from the value of kinetic energy to obtain the work function.
Another way is if you are given the value of energy of photon at 0KE (maximum wavelength or minimum frequency): in this case Ephoton = work function

Gabriela Aguilar 4H
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Joined: Fri Sep 28, 2018 12:29 am

Re: Work Function

Postby Gabriela Aguilar 4H » Thu Oct 25, 2018 8:53 pm

You would just rearrange the equation EK = h v - workfunction
to solve. The Ek should be given if you are looking for workfunction.

g orloff 1J
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Joined: Fri Sep 28, 2018 12:16 am

Re: Work Function

Postby g orloff 1J » Thu Oct 25, 2018 8:57 pm

use the equation Ek=hv-work function to find what you are looking for and use algebrato re arrange.

mayra martinez 1D
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Joined: Fri Sep 28, 2018 12:17 am

Re: Work Function

Postby mayra martinez 1D » Thu Oct 25, 2018 11:34 pm

If you use the equation Ek= hv-work function you can set it up as: work function= hv-Ek and you can just substitute for h, v and Ek. Depending on what you're given just know that you can always switch around the equation to fit to what you need and that you can use other equations to help you solve for some variables.

Karina Jiayu Xu 4E
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Joined: Fri Sep 28, 2018 12:29 am

Re: Work Function

Postby Karina Jiayu Xu 4E » Sun Oct 28, 2018 1:24 pm

Is the work function the same as the threshold energy?

Lasya Gudipudi 1A
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Joined: Fri Sep 28, 2018 12:15 am

Re: Work Function

Postby Lasya Gudipudi 1A » Sun Oct 28, 2018 1:39 pm

The work function specifically refers to the minimum amount of energy required to eject an electron, and the threshold energy refers to the frequency that light has to reach to eject an electron. However, when calculating using the equation, they are the same thing, which is why Professor Lavelle uses these terms interchangeably.

105085381
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Joined: Fri Sep 28, 2018 12:15 am

Re: Work Function

Postby 105085381 » Mon Oct 29, 2018 1:11 pm

The equation Ek=hv-work will always help you find your solution, in this case!

305115396
Posts: 30
Joined: Fri Sep 28, 2018 12:16 am

Re: Work Function

Postby 305115396 » Sat Nov 03, 2018 11:39 pm

Solve for the work function using the equation Ek = hv – work function. Usually the problem will give you the info needed to plug in values into this equation. The work function is usually in joules.

Abhi4F
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Joined: Fri Sep 28, 2018 12:28 am

Re: Work Function

Postby Abhi4F » Sun Nov 04, 2018 6:48 pm

Using the equation, Energy of photon = work function + kinetic energy, you can solve for work function given the other variables.

705022748
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Joined: Fri Sep 28, 2018 12:25 am

Re: Work Function

Postby 705022748 » Thu Nov 15, 2018 10:31 pm

Use Ek=hv-work to solve for work functions and use other variables given in the problem to plug in!

Jack Hewitt 2H
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Joined: Fri Sep 28, 2018 12:27 am

Re: Work Function

Postby Jack Hewitt 2H » Thu Dec 06, 2018 6:11 pm

Melissa Villanueva 3D wrote:How would we solve for the work function? Like what type of information would be given to use in order to find the work function and how would we use the given. Thanks!

You rearrange the formula as you would with an algebraic equation and plug in what is given to solve for the work function.

Nina Do 4L
Posts: 61
Joined: Fri Sep 28, 2018 12:27 am

Re: Work Function

Postby Nina Do 4L » Thu Dec 06, 2018 9:23 pm

Work function, threshold energy, and ionization energy all mean the same thing and can be used interchangeably. The equation you'd use is ephoton - work function (or threshold or ionization energy) = Ekinetic energy, 1/2mv^2.
Based on the information of the problem, you can work backwards to find one component which will usually allow you to find another component based on the manipulations of the light problems that are given on the front cover of the test. Hope that helps!

sarahartzell1k
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Joined: Fri Sep 28, 2018 12:17 am

Re: Work Function

Postby sarahartzell1k » Thu Dec 06, 2018 11:10 pm

Use the equation EK = h v - workfunction to solve.

Ahmed Mahmood 4D
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Joined: Fri Sep 28, 2018 12:28 am

Re: Work Function

Postby Ahmed Mahmood 4D » Fri Dec 07, 2018 9:42 pm

The work function can be thought of as the amount of energy required to discharge an electron from a metal surface. As such, the energy of the incoming photon-the work function=the kinetic energy of the discharged electron. The work function is sometimes given, but it can also be algebraically determined by working with the equation and the knowledge of the energy of the incoming photon and the kinetic energy of the discharged electron.


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