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Homework help needed by 10pm tonight

  1. Sep 19, 2005 #1
    hey guys idk how you know all this stuff, and id appreciate if you helped me. i have to do wavelength and and frequency problems and i dont really understand how to do it the way my teacher taught it, so here they are and thanks for helping me.

    1.The frequency of yellow light is 5.5 1014 Hz. Find the wavelength of yellow light. The speed of light is 300 000 km/s.

    2.AM radio signals are broadcast at frequencies between 570 kHz and 1580 kHz (kilohertz) and travel 3.0 108 m/s.

    (a) What is the range of wavelengths for these signals? (Enter the wavelengths from shortest to longest.)
    ____m to ______ m
    (b) FM frequencies range between 88 MHz and 108 MHz (megahertz) and travel at the same speed. What is the range of FM wavelengths?
    ______ m to _____ m

    3.The velocity of a wave on a string depends on how hard the string is stretched, and on the mass per unit length of the string. If FT is the tension in the string, and ยต is the mass/unit length, then the velocity, v, can be determined.
    http://i20.photobucket.com/albums/b...o5/physicsq.gif [Broken]
    heres a pic of the formula i have to use

    A piece of string 5.30 m long has a mass of 17.0 g. What must the tension in the string be to make the wavelength of a 120 Hz wave 120.0 cm?

    thanks again
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Sep 19, 2005 #2


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    Science Advisor
    Homework Helper

    This query looks amazingly similar to another post you recently made. :uhh:
    For the first two questions, I would first start by looking up the relationship between wavelength, frequency and speed of light in your text.
    You should find the relationship is a simple linear equation; with a constant equal to the product of two variables. See if you can determine your answers using that equation.
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