1. Not finding help here? Sign up for a free 30min 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!

Lightsorce through spectrometer

  1. Mar 3, 2015 #1
    1. The problem statement, all variables and given/known data
    A light hits a spektrometer perpendicular into a gitter with 300 slits/mm. You observes that a red and a blue line (in Visual light) coinciding. And the angle deflectionis 24.5°. What wavelenght have the red and the blue lines.
    No n is given.

    2. Relevant equations
    d*sinα=n*λ

    3. The attempt at a solution
    First i calculated d
    1/300000m = 3.33*10-6
    ((3.33*10-6)*(sin24.5))/625-9 2.5

    ((3.33*10-6)*(sin24.5))/500-9 2.5

    Answer:
    so the red wavelenght is 625nm
    so the blue wavelenght is 500nm
    n=2.5

    Is this correct ? can it be 2.5?? the blue is closer to n3 and red n2
     
  2. jcsd
  3. Mar 3, 2015 #2

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    So, I take it that "gitter" is "grating".

    I get approximately 2.2 and 2.7 as shown above in RED.

    So, yes, use n = 2 for red & n = 3 for blue.
     
  4. Mar 3, 2015 #3

    TSny

    User Avatar
    Homework Helper
    Gold Member

    Hello, SwedishFred.

    You know that n must be an integer, so n cannot be 2.5. Think about this: Is it possible for two different wavelengths to overlap using the same value of n for each wavelength?
     
  5. Mar 3, 2015 #4
    No that was what i was thinking about, so I understand it now, its much easier to see it happend ;-)
    Thanx
     
  6. Mar 3, 2015 #5

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    What do you get for the two wavelengths?
     
  7. Mar 3, 2015 #6
    ((3.33*10-6)*(sin24.5))/2
    ((3.33*10-6)*(sin24.5))/3
    Red 690nm
    Blue 461nm

    True ?
     
    Last edited: Mar 3, 2015
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Lightsorce through spectrometer
  1. Mass Spectrometer (Replies: 1)

  2. Grating Spectrometer (Replies: 2)

  3. Spectrometer CCD (Replies: 1)

  4. Mass spectrometer (Replies: 1)

Loading...