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Questions about light(wave and dual nature)

  1. Jan 20, 2014 #1
    Ok, so I have many questions about light. My basic understanding can be seen here:
    My first question is, consider transverse waves in water. As the wave moves out, the water molecules move up and down forming the crests and troughs. Considering light, as light moves out, if my understanding in the link above is correct, then the FIELDS are oscillating, i.e. changing in magnitude(in place of the water molecules), and along the line that the light moves(not actually up and down in space,like the water molecules). The frequency is the number of times the strength of the field goes from maximum to minimum and back to maximum in a second, and the wavelength is the distance the light travels when one such cycle is completed.
    If what I have said above is right, how can this be translated to wavelengths of material particles(say like a photon). It is not possible for the material particle to oscillate at a point, right?
  2. jcsd
  3. Jan 20, 2014 #2


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    Staff: Mentor

    Your understanding is mostly correct. The oscillation is the electric and magnetic field vectors. That is, the field "points" in a particular direction that oscillates back and forth. So when the EM wave interacts with an antenna it will cause the charges to move in one direction and then the other.

    How does this relate to a photon? The short answer is that the EM wave interacts with matter only in discrete packets of energy that we call photons. This means that the photon isn't a particle in the sense of being a hard little ball and it is not a wave in itself. It is a manifestation of how the EM wave interacts with everything else.
  4. Jan 20, 2014 #3
    Thanks. So, in the same way, particles like electrons are particles only when they interact with something else(other particles, say a proton in this case) and otherwise they can be considered to be waves? So the wavelength here does not mean the particle rides along a 'loop' but rather it refers to the wave nature of the particle, which only manifests itself as a particle during interactions? And, lastly, in the case of light, the fields are oscillating. When a particle like an electron moves, what is oscillating?
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