# Homework Help: Photoelectric Effect

1. Dec 11, 2016

### Ekramul Towsif

1. The problem statement, all variables and given/known data
X·ray is produced when an electron is incident on a metal surface with $2x10^8 ms^-1$ velocity
.Applying this X-ray on the surface of two metals having work function of 5 eV and 2.3eV, photoelectric effect is observed.
e by

2. Relevant equations

3. The attempt at a solution
$E = K_{max} + \phi$
$hf = \frac 1 2mv^2 + hf_o$

i got stucked here. i dont know what to do next

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Last edited: Dec 11, 2016
2. Dec 11, 2016

### Cutter Ketch

Your post is difficult to read, and confused. Could you more accurately produce the question as it was asked?

3. Dec 11, 2016

### Ekramul Towsif

which part or portion is difficult to undestand ?

4. Dec 11, 2016

### Cutter Ketch

Well this is very interesting. I would have quoted the confused questions in the OP: the lack of a part a or b, the fact that part d was neither a sentence nor a question nor in fact an intelligible phrase, but it appears you've edited the post. Now there are no questions at all and you've pasted in a picture of your problem. Now here's the interesting part. Although better than the OP, the question as given to you is pretty confused. I presume that whoever wrote it speaks something other than English as a first language. Ok, well let's see what we can do.

From your unedited OP I presume you've answered a and b. For c you posted an energy equation which appears to be for scattering in that there is an h f0. Here there is no h f0. The electron does not necessarily have to give all of its energy to a single X-ray, but that is the most it can do, so I think that is what they want you to assume. So what is the frequency of the x-ray if all of the kinetic energy of the electron produces one x-ray photon?

The last part seems to be asking if that frequency of an X-ray can liberate an electron given the two work functions. Well, does it have enough energy?