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Homework Help: Pls help Diffraction problem

  1. Aug 3, 2006 #1
    I know i'm just a newbie, but i need your help guyz :blushing:
    This is a matter of life and death :surprised Thanks!!!

    --> In conventional television, signals are broadcast from towers to
    home receivers. Even when a receiver is not in direct view of a tower because of a hill or building, it can still intercept a signal if the signal diffracts enough around the obstacle, into the obstacle's “shadow region”. Current television signals have a wavelength of about 50cm, but future digital television signals that are to be transmitted from towers will have a wavelength of about 10mm. (a) Will this change in wavelength increase or decrease the diffraction of signals into the shadow regions of obstacles? Justify your answer with physics. Now, assume that a signal passes through an opening of 5.0m width between too adjacent buildings. What is the angular spread of the central diffraction maximum (ie how large of an angle does the central maximum occupy) for wavelengths of (b) 50cm, (c) 10mm?
  2. jcsd
  3. Aug 3, 2006 #2

    Andrew Mason

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    To begin, tell us what you know about diffraction.

  4. Aug 3, 2006 #3
    Diffraction is the spreading of waves around obstacles or squeezing through a small hole. It occurs with sound waves, light, atoms, and subatomic particles. Its like if light waves from 2 slits can interfere
    with each other, the light from different parts of the same slit also interfere.

    I'm really not good in Physics, i already answered 2/4 of my homework but i can't do this and the other one. I really need help coz this is 15% of my total grade, and this is due tomorrow. Thanks...
  5. Aug 4, 2006 #4


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    For question (a), you need only ask yourself "when is the effect of diffraction most noticeable?" (Think in terms of wavelength). For questions (b) and (c) you will need a formulae. What formulae do you know which can describe the diffraction pattern of a single slit?
  6. Aug 4, 2006 #5
    Oh ok, i already passed my HW this morning. So, thanks anyway ;)
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