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Homework Help: Confused about the speed of a wave

  1. Apr 14, 2015 #1
    1. The problem statement, all variables and given/known data
    Actually its not a homework problem sort of thing.....I was wandering through a book , studying waves then I realised that there were two formula for the same thing .....the velocity of a wave.

    2. Relevant equations
    v=λ/T [where λ is the wavelength and T is the time period]
    V=√(T/μ) [where T is tension and μ is linear mass density]

    3. The attempt at a solution
    I dont know.......are both of these correct and I am relating two different things ? or both of them are applied at different places .... I just dont get it....help needed.....

    Edit: Is it like that velocity of a wave is defined by the second formula and the first formula is just a relation between λ and T where v is a constant .[ Just like in the case of resistance in dc circuits where R=ρl/A actually defines Resistance whereas V=RI is just a realtion between V & I where R is just a constant]
    Last edited: Apr 14, 2015
  2. jcsd
  3. Apr 14, 2015 #2


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    Your first expression is general and does not depend on the type of wave. It is derived essentially from basic wave motion and from how we define the wavelength and period.

    The second expression is the speed of a transversal wave on a string. Using both expressions, you could essentially derive a relationship between the period and the wavelength in terms of the tension and the linear mass density for this type of wave.
  4. Apr 14, 2015 #3
    Okay i got it now. Both of them are correct.....It is just that first one is general whereas 2nd one is for the particular case of a transversal wave.
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