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!

Homework Help: Balmer's Formula.

  1. Apr 16, 2008 #1
    [SOLVED] Balmer's Formula.

    1. I am to find the formula of each series of wavelengths:
    • 12500, 31.25, 13.90, 7.81, and 5.00 nm
    • 375, 900, 1575, 2400, 3375, and 4500 nm
    ***Also, n might not always equal 1.

    2. [tex]\lambda[/tex] = [tex]\frac{94.18 nm} ({\frac{1}{m^{2}}) - (\frac{1}{n^{2}})}[/tex])
    Where m = 1, 2, 3, ... and n = m+1, m+2, ...​

    3. My prof said that all I had to do was plug and chug, but I am not exactly sure what she meant by that, and do I assume that m is just zero at times?
    I want to know if there is a way I can do this mathematically? She told me to THINK squares, so I attempted to take the square root of the numbers.

    Any guidance will be appreciated.
  2. jcsd
  3. Apr 16, 2008 #2
    I wanted to clarify since I seem to have found the second one, it is talking about finding a FORMULA, so Balmer's formula is really useless in a way.

    If a Mod would rename this I would really appreciate it, rename it to: Finding Formula given a series.
  4. Apr 16, 2008 #3
    And I just figured out the second one, what a waste of forum-space!

    Thanks anyway!

  5. Apr 16, 2008 #4
    One way is to take differences between succesive numbers, and see if a pattern emerges.
    Take the differences of the differences is that doesn't work. If the differences are constant after n steps the numbers can be produced with a n'th degree polynomial.

    since the numbers are wavelengths, you could try the frequencies as well.

    I think the first number from a needs to be 125.00
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook