Sampling HW Q4

[Xinying Wang_3C]

For Q4 in the homework, I understand I need to find E through E=hv, but how I proceed from there? I am quite confused about how to find the work function.

Thanks in advance!

[Isaias Gomez D3A]

well, the energy of the photons that you calculated minus the threshold energy (work function) equals the kinetic energy of the emitted electrons. So you can find the threshold energy by simply subtracting the kinetic energy of the electrons (given) from the energy of the photons (calculated).

[Evie Li_1H]

Keep in mind that you should use E=1/2mv^2 when finding the kinetic energy of electrons. The c=lambda(v) and E=h(frequency) only works for finding the energy of photons.

[KhanTran3K]

Hey!
Like the others said, (E=hv) - (work function) = kinetic energy(1/2mv^2). Since they give us kinetic energy and the frequency, we can find the work function by subtracting the E by the kinetic energy. I would also like to add on that for the rest of question 4, it asks for the maximum amount of electrons that can be ejected. Since we know one photon can result in on ejected electron, we can divide the total energy that they give us by the work function, since this would give us the total amount of photons, which equals the amount of electrons. Hope this helps!

[Haochen He 3L]

Hi!
You should use E of photo to minus the kinetic energy of the electron (mv^2/2) in order to get the work funtion.

[jia207]

Use simple algebra to arrange the question to fit what you need! The equation can be found on the formula sheet and other students have posted what it is already above. You got this :)