Questions from Discussion

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Lily Mohtashami
Posts: 142
Joined: Wed Sep 30, 2020 9:34 pm

Questions from Discussion

Postby Lily Mohtashami » Sun Oct 18, 2020 7:53 pm

When a metal was exposed to photons at a frequency of 1.42*10^15s^-1, electrons were emitted w a maximum kinetic energy of 3.90*10^-19J. What is the maximum number of electrons that could be ejected from this metal by a burst of photons w/ a total energy of 6.22*10^-7?
Can someone help explain how to find maximum number of electrons ejected?

Chanel Mao 3D
Posts: 88
Joined: Wed Sep 30, 2020 9:52 pm
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Re: Questions from Discussion

Postby Chanel Mao 3D » Sun Oct 18, 2020 8:00 pm

Hi!
You can first calculate the work function (Energy of the photon - the kinetic energy of the electron), which should be 5.51*10^-19 J/photon. Then, you divide the total energy (6.22*10^-17 J) by the calculated work function (5.51*10^-19 J/photon) to get the number of photons. Since one photon has the capability of ejecting one electron, the maximum number of electrons ejected should equal the number of photons there are. Hope this helped!

Joseph Hsing 2C
Posts: 85
Joined: Wed Sep 30, 2020 9:42 pm

Re: Questions from Discussion

Postby Joseph Hsing 2C » Sun Oct 18, 2020 10:05 pm

After calculating the work function by subtracting max KE from energy of the photon, you should then divide total energy by the work function. The answer should be the max number of electrons ejected!


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