Kinetic Energy

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Jason Slater 3I
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Joined: Wed Sep 21, 2016 2:58 pm

Kinetic Energy

Postby Jason Slater 3I » Wed Sep 28, 2016 8:44 pm

What role does kinetic energy play in the photoelectric effect? I know that you use the Kinetic (excess) energy as a part of an equation to find the energy of a photon or the threshold energy, but in the real life experiment, what is the purpose of the excess kinetic energy? What does it do or tell us/ what happens to it?

Mikaela Gareeb 3G
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Joined: Wed Sep 21, 2016 3:00 pm

Re: Kinetic Energy

Postby Mikaela Gareeb 3G » Wed Sep 28, 2016 9:09 pm

Total energy-threshold energy=excess energy describes the photoelectric effect in steps. In other words, a certain amount of energy is inputed by a photon and the process of removing an electron takes up some energy, but if there is some left over, then the electron takes the excess/kinetic energy with it as it leaves the system. The reason for the excess/kinetic energy is due to the conservation of energy. Furthermore, after the threshold is reached (i.e the frequency is high enough) then the intensity can increase which results in more kinetic energy being carried out released electrons. I would assume that the higher the kinetic energy, the higher the intensity.

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Re: Kinetic Energy

Postby Joseph_Ghaly_2L » Wed Sep 28, 2016 11:22 pm

Does the equation only hold true under the assumption that the electrons carry no rotational kinetic energy? Why is only translational kinetic energy included in the equation?

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Joined: Wed Sep 21, 2016 3:00 pm

Re: Kinetic Energy

Postby Navarro_Bree_1D » Thu Sep 29, 2016 4:55 pm

I think the equation does not include rotational energy because rotational energy at the atomic level is not significant enough to take into account. The moment of inertia is extremely small.

Soonwoo Chung 1D
Posts: 26
Joined: Wed Sep 21, 2016 2:57 pm

Re: Kinetic Energy

Postby Soonwoo Chung 1D » Thu Sep 29, 2016 9:02 pm

So when there is excess energy, which causes the light to bounce off, is the excess energy all kinetic energy? or is it an addition to the electrons and only intensifies the light? So what I'm asking is whether the kinetic energy itself is what is creating the light or just making it stronger.

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