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Beginner questions

  1. Jun 5, 2006 #1
    1. I've looked at a beginner guide to quantum mechanics and a saw the probability illustration of an atom. It didn't seem quite continuous what leads me to the question: Is the motion of quantums discrete?

    2. How do we know quants exist if we can't see them?

    3. How do I have to visualize electromagnetic waves? After all, they have to be spacial, and space can be displayed with geometry - and geometry is rational. How thick are the layer waves in width? What's the radial displacement angle between two electromagnetic waves emitted from a diffuse light source? If they are an in-between of particle and waves: What is the in-between?
  2. jcsd
  3. Jun 6, 2006 #2
    Question number 3 is something I've been pondering about myself. For some reason or another I feel the need to visualize everything in my head for better understanding :)
  4. Jun 6, 2006 #3
    An electromagnetic wave consists of two perpendicular waves: an electrostatic and magnetic field. They obey Maxwell's equations.
  5. Jun 8, 2006 #4
    Like this:
    http://img122.imageshack.us/img122/6122/elec7zg.jpg [Broken]
    Last edited by a moderator: May 2, 2017
  6. Jun 8, 2006 #5
  7. Jun 8, 2006 #6
    Indeed not only the motion of quantum world but the motion of classical world are also discreat. For example, the energy of system of harmonic oscilator [tex]E=\frac{p^2}{2m} + \frac{1}{2}kx^2[/tex] is not continuous ;but, the discreated value is very small which is in magnitude of plank's constant. For quantum scale, this value is obvious.

    For the second question, I think the word of 'quants' mean to quanta. No one could see a quanta. It is just only the human idea for describe the nature. Luckily, it seems to quite paint the real picture of god.

    Finally, the derivation of Maxwell equations can write:
    [tex]\vec{B}=\hat{k} \times \vec{E}[/tex]
    the magnetic field is perpendicular to the electric field.
  8. Jun 8, 2006 #7
    So everything in our visible universe is basically just appearing and diappearing tiny parts of matter, i.e. quanta?
    I don't know any scientific constants except pi and e, hahaha, I'm not in college yet :blushing: :biggrin:

    O.k. you got me on that one, but:

    the singular of quanta is a quantum :p

    Thanks for the helpful information!
  9. Jun 8, 2006 #8


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    The probability distribution of an electron in an atom (say hydrogen) is continuous.
    You can't draw a graph of it, since you need to assign a value (the probability) to each point in space. So usually they show level surfaces, maybe that's what made it seem discontinuous.

    The energy levels of an electron in an atom are discrete, not it's position. And we know it's true, because it's been measured very accurately.

    I visualize an electromagnetic wave like any other EM-field. A continuously distributed bunch of vectors if you will, except that the bunch moves with the speed of light. EM-fields are really part of the classical picture of light. No particles (photons) come into play, but you can consider an EM-wave as being made up of a myriad of photons if you like.
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