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Does a gamma ray photon have less energy than a radiowave photon?

  1. Jul 12, 2011 #1
    I'm wondering because the gamma ray photon is smaller yet it has a higher frequency. Is it because the amount of energy that passes a single point in a second for a gamma ray is higher than that of radio waves, since a lot more photons are passing that single point that in other em radiation?
     
  2. jcsd
  3. Jul 12, 2011 #2
    First, you have several misconeptions going here. One photon is not smaller than another. The wavelength or frequency might be smaller, but the photon itself isn't "smaller". Second, although the energy comes in packets, it isn't that a gamma photon has more packets than a radio photon - it just has more energy, related by E = hf.
     
  4. Jul 12, 2011 #3
    So, all photons are the same size? Do they all have the same amount of energy or does it differ between wavelengths? I actually didn't say that gamma rays have more photons, just that more photons pass a single point in a second than radio waves.
     
  5. Jul 12, 2011 #4
    You asked about the energy of a single photon.
    And the answer is that a gamma photon has a lot more energy than a microwave photon.
    The energy of a single photon is given by plank's formula, see daveb's post.
     
  6. Jul 12, 2011 #5

    Drakkith

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    Photon's do not have a physical size like you would normally think of. The consist of an oscillating Electric and Magnetic field. The faster they oscillate the more energy the photon has. EACH photon has its own frequency and energy. The highest energies and frequencies are associated with X-Ray and Gamma Ray photons. Radio waves have MUCH lower energy and frequency, and hence a much longer wavelength. (Wavelength and Frequency are inversely proportional. The higher the frequency the shorter the wavelength and the lower the frequency the longer the wavelength.)
     
  7. Jul 12, 2011 #6
    Oh right, I must have misread something I read earlier but I have a better understanding now. What do you mean exactly by oscillating electric and magnetic fields?
     
  8. Jul 12, 2011 #7

    Drakkith

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    Per wikipedia: Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states.

    If you look up Photon online, you will see a picture of two waves, one up and down and the other side to side. Oscillating just means that the amplitude of the wave is moving from positive to negative and back. The electric and magnetic fields both switch between their positive and negative at whatever frequency the photon is.
     
  9. Jul 12, 2011 #8
    Oh, that explains so much. Also, do the photons in a ray of light touch each other? Well not touch each other since they have no mass, but are they close in position to each other? When light travels, does it actually travel like a wave, so each photon travels in a different direction while traveling in a straight line? (similar to a snake) One last question, (sorry about all of these, I find light very interesting) why does light travel so fast? (relative to us)
     
  10. Jul 12, 2011 #9

    Drakkith

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    The view of a photon as a particle, IE a little ball travelling along the wave, is incorrect. Light IS an oscillating electromagnetic wave. It is not a little ball. It is only a "particle" in the sense that it carries with it a certain amount of energy that isn't dissipated during travel.

    Photons are bosons, not fermions, and as such do not obey the Pauli Exclusion Principle. They can and do travel "through" other photons. Fermions are particles such as Protons, Neutrons, and Electrons. The exclusion principle describes the observation that no two of those particles can occupy the same spot in space AND have the same Quantum Numbers. (Which describe the properties of each particle, such as energy level and spin) It is a direct result of that principle that matter has volume. Most of the atoms that make up all matter is simply empty space. It only has volume because the electrons cannot occupy the same spots and cannot get close to the nucleus on average.

    Light travels at a velocity called c. It is a fundamental constant in science and is 299,792,458 meters per second. Light travels at this speed because it is massless.

    If you want more on any of this I highly recommend seaching wikipedia on anything above. There is a wealth of information there.
     
  11. Jul 12, 2011 #10

    Redbelly98

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    Rays of light are an antiquated notion. They are still useful for calculating what a lens or mirror does, but the idea was long abandoned by the time people started the whole "wave vs. particle" discussion.
     
  12. Jun 26, 2012 #11
    hi guys...i am really confused about some stuff regarding em radiation...

    Radiations of all kinds have same energy (speed) but differing frequencies....but then, why do photons of different frequencies have different energy contents (E = hf)?
     
  13. Jun 26, 2012 #12

    Drakkith

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    Radiation does not have the same speed unless it is em radiation which moves at the speed of light. The energy can vary wildly as well. The energy of a photon is directly related to its frequency by e=hf because it only has one speed, unlike particles that have mass which can have any speed under the speed of light.
     
  14. Jun 26, 2012 #13

    ZapperZ

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    If I have a system that does a certain amount of work W in one cycle, then if the system does 10 cycles per second, I have 10*W amount of work done in one second.

    What if I have a system that has a higher number of cycles per second, say, 20 cycles? Then the amount of work in one second is 20*W, which means MORE work in one second.

    And since "frequency" is nothing more than the number of cycles (complete oscillation) per second, I've just shown you a reason why higher frequencies produces more energy, assuming everything else being the same!

    Zz.
     
  15. Jun 26, 2012 #14

    Redbelly98

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    Energy and speed are not the same thing.

    p.s. welcome to PF.
     
  16. Jun 29, 2012 #15
    I was talking about EM radiations only..
    hmmmm.:confused:. I think I've got a misconception - I always thought that the different kinds of EM radiations have the same energy.
     
  17. Jun 29, 2012 #16

    Drakkith

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    Nope. The energy of the visible spectrum ranges from about 1.5 eV on the red end, to about 3 eV on the blue end.
     
  18. Jun 29, 2012 #17
    ohk...! This cleared my initial doubt as well! tyvm guys!
     
  19. Jun 29, 2012 #18
    nope.
    light, for example, does not penetrate your skin much; hence more energetic X rays
    are needed to show what is underneath...they have the energy to penetrate surface skin. Another example: light is warm and conveys some energy you can feel, but microwaves [as in a microwave oven] get the heating job done a lot faster...as described above by Zapper.
     
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