Photoelectric Effect

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Tiffany_Cacy_3D
Posts: 70
Joined: Fri Sep 28, 2018 12:24 am

Photoelectric Effect

Postby Tiffany_Cacy_3D » Thu Oct 11, 2018 4:06 pm

I am taking the post-module test for the photoelectric effect module and I am having trouble with number 28. So the information given is the velocity and the work and the work function. Because it is asking for the Kinetic Energy I assume you would need to use the formula E=1/2(MV2) but I am not sure how to get M in order to complete the question. Am I using the wrong formula? Any help is appreciated!
This is the question for context..
28. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1.
Answer the following three questions.
A. What is the kinetic energy of the ejected electron?

caseygilles 1E
Posts: 73
Joined: Fri Sep 28, 2018 12:18 am

Re: Photoelectric Effect

Postby caseygilles 1E » Thu Oct 11, 2018 4:58 pm

The mass of an electron is the same in each problem regardless of the metal that the election is emitted from. The mass of an electron is 9.10938356 × 10^-31 kilograms.

Meachelle_Lum_1I
Posts: 92
Joined: Fri Sep 28, 2018 12:24 am

Re: Photoelectric Effect

Postby Meachelle_Lum_1I » Thu Oct 11, 2018 5:27 pm

Kinetic energy is calculated by 1/2mv^2. Use the given velocity in the problem and the mass of an electron (9.11*10^-31 kg), and substitute these values into the equation.


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