Recent content by echaniot

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    I Is Photon Mass Zero or Relativistic in Nature?

    @ DrStupid, very much correct. Thanks !
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    I Is Photon Mass Zero or Relativistic in Nature?

    Actually, on relativistic mass you can think of it this way: The total energy of a point mass in motion can be given by the formula: E = T + mc**2 In case u <<c , E = 1/2 * mu**2 + mc**2 (1) T_cl = 1/2 * mu**2 while, when u->c, E = (γ-1)*mc**2 + mc**2 (2) T_rel =...
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    Teaching High School and Pursuing a Ph.D. in Physics: Is It Possible?

    Totally agree with Choppy, as I happen to belong in the latter category. Do your PhD, but even so, you have a couple of semesters to go. Have you ever taught (even informally)? Have you considered the possibility that if you start teaching before doing your PhD, the timescales will be really...
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    Where Can Physics Teachers Find Valuable Teaching Resources?

    You can also find many ICT-based educational resources and participate in relevant communities here: www.inspiringscience.eu as well as here: portal.opendiscoveryspace.eu
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    Electrons absorb exact energy photons so how is Ek possible

    This means for example that we cannot observe Raman scattering (which has negligible yet not zero cross section) from the 10.3 eV photons when we shoot them at hydrogen?
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    Electrons absorb exact energy photons so how is Ek possible

    Agreed, but in the case between the fundamental and the first excited state we are not (yet) in the high quantum numbers realm. In this part, the energy difference between the different states is of order 0.1 eV or less, whereas here we are dealing with ~1 eV differences. The conservation of...
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    Electrons absorb exact energy photons so how is Ek possible

    Yes, but here we don't speak of energies greater than the ionisation energy You say: ----------------------------------------------------------------------- For the simple case of an atom in a gas, the well known rules of QM apply (as in the hydrogen atom we all know and love). A very high...
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    Electrons absorb exact energy photons so how is Ek possible

    So , sophiecentaur what you suggest is that if we bombard a hydrogen atom in its ground state with 10.3 eV photons, it will not absorb them (and thus be excited) , because they don't have the correct energy (10.2 eV sharp) to jump to the first excited state?
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    Can Coherent Light Waves Interfere with Each Other?

    As an addition to ZapperZ's answer, this QED process is called Delbruck scattering . Photon's spontaneously create virtual electron-positron pairs which interact. This is actually one of the most prominent mechanisms of gamma ray attenuation in high energy astrophysics.
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    Electrons absorb exact energy photons so how is Ek possible

    I think that the extra energy goes to the whole atom: If (e,g) you have a hydrogen atom with an electron in the ground state n=1 (E1=-13.6 eV), then to take it to the first excited state n=2 (E2 = -3.4 eV), you need to provide it with 10.2 eV of energy. To take it to the third from the second...
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    Do I stand a chance as a physicist?

    Good afternoon from Greece! First of all, I want to congratulate you on following your passion in life. It is not an easy decision to drop out from school for pursuing your dream, and once you realize it didn't fulfill your expectations , start all over. If you have such a drive for science...
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    Question on electron straggling in matter

    Good afternoon, I am trying to simulate the propagation of electrons in copper. To do so, I fill a Landau distribution with mean the most probable value of energy loss. However, my formula doesn't seem to work as I find that I can have higher energy loss than the electron energy itself! Could...
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    Optimizing Copper Absorber Depth for Beta Spectra Simulation

    Hello, I am interested in computing the optimal depth of a copper absorber for Sr-90 decay electrons. I want to find a way to simulate a beta decay spectrum in C++. Have you got any idea or possible documentation on where I could start?? Thank you!
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    Could There Be a 5th Force at Lower Energies?

    Hello there, there is a nice book speaking of the tests conducted on the hypothesis of a fifth force. https://www.amazon.com/dp/1563961199/?tag=pfamazon01-20 There is research going on on some new experiments (At JLab and GSI), where they try to detect some new gauge bosons A' (popularly named...
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    Co60, Gamma Spec, Different Counts in Peaks

    It is not necessarily *only* photoelectric effect that takes place there. It could be successive compton scattering with all the energy absorbed within the detector, taken that the detector is thick enough. A 10% effect is an order of magnitude difference in counts and thus in the cross...
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