Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Just one harmonic motion problem

  1. Mar 1, 2004 #1
    Problem 17.
    The speed of all elctromagnetic waves in empty space is 3*10^8 m/s.
    What is the wavelength of X rays emitted at 3.2*10^12 MHz? Answer in m.
    This is what I have done;
    wavespeed=frequence times wavelength
    3*10^8/3.2*10^12 = 9.375 * 10 ^-5 m
    I got this answer for the problem but when I submitted the answer it was wrong, what did I do wrong?
     
  2. jcsd
  3. Mar 1, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    The frequency was given in MHz; you need to convert to Hz. 1 MHz = 10^6 Hz.
     
  4. Mar 1, 2004 #3
    Reply

    Would it then be 3.2*10^12MHz * 10^6Hz=3.2*10^19 Hz
     
  5. Mar 1, 2004 #4
    Re: Reply

    12 + 6 = ?????
     
  6. Mar 1, 2004 #5
    So himanshu121 it would really be 3.2*18. Since you pointed out 12+6=18?
     
  7. Mar 2, 2004 #6
    Dear it is 3.2 * 1018 Hz now apply the formula u will get it
     
  8. Mar 2, 2004 #7
    Reply

    So by dividing 3*10^8 by 3.2*10^18 = 9.375*10^-11 is the answer?
     
  9. Mar 2, 2004 #8

    Doc Al

    User Avatar

    Staff: Mentor

    Re: Reply

    Yep. Your original answer was off by a million, since you used the wrong units for frequency.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook