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Homework Help: How to produce a standing wave question

  1. Dec 20, 2011 #1
    1. The problem statement, all variables and given/known data
    using a wire of length L= 1 M with both ends fixed, can you produce a standing wave with the following wavelengths? Explain why or why no.

    a. 30 cm:

    b. 1m :

    c. 75 cm :

    d. 2 m :


    2. Relevant equations
    L=n. (λn/2)


    3. The attempt at a solution

    1m= n. 30 cm/2 ?
     
  2. jcsd
  3. Dec 20, 2011 #2

    HallsofIvy

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    Science Advisor

    A standing wave must fit a full "wave" inside the given length. In other words the length must be an integer multiple of the wavelength.
     
  4. Dec 20, 2011 #3
    So would all of the wave lengths work except for the 2 meter one?And How can I explain it with the formula?

    Thank you for your help.
     
  5. Dec 20, 2011 #4

    berkeman

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    Staff: Mentor

    For a string or wire fixed at both ends, the fundamental mode fits a half wavelength between the nodes, no?
     
  6. Dec 20, 2011 #5

    berkeman

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    Staff: Mentor

    Welcome to the PF.

    I'd suggesting sketching each of the possible answers, to see if you get a whole number of half wavelengths between the nodes.
     
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