1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fundamental Frequency

  1. Jan 6, 2005 #1
    Which of the following could be the fundamental freq. for a vibration that has an overtone freq. of 990 Hz?

    a. 330
    b. 660
    c. 148
    d. 1980
    e. 1990
    (All in Hz.)

    The formula that I think you have to use is f_n = n*f_1, where f_1 is fud. freq.

    Then, I thought

    f_2 = 2*f_1, where f_2 is the overtone freq. (is these a correct assumption?)

    but 990/2 is 495.

    Could someone direct me to the correct path of getting the solution?

    I'm confused over the definitions of overtone and fund. freq.

    Last edited: Jan 6, 2005
  2. jcsd
  3. Jan 6, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There's no reason to assume than n=2, so you just leave it as n.

    So you have [itex]f_n = nf_1 [/itex]
    Or [itex]f_1 = \frac {990}{n} [/itex]

    Which of the choices satisfies this condition for some integer n ?

    Can you say if [itex]f_1[/itex] will be greater than or less than 990 Hz, from this ? Does this rule out any choices ?

    The alternative is simply to notice that [itex]f_n/f_1 = n [/itex], so try the remaining choices of [itex]f_1[/itex] to see which one gives you an integer ratio.
    Last edited: Jan 6, 2005
  4. Jan 6, 2005 #3
    Is the answer A?

    The fud freq. would be less than 990, would it not? That leaves A and B, and 990/3 is 330.
  5. Jan 6, 2005 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That's right.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Fundamental Frequency
  1. Fundamental frequency (Replies: 2)

  2. Fundamental frequency (Replies: 3)

  3. Fundamental Frequency (Replies: 5)

  4. Fundamental Frequency. (Replies: 2)