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!

Diffraction grating question

  1. May 31, 2012 #1
    Question: Light from a slit passes through a transmission diffraction grating of 475 lines/mm, which is located 2.8m from a screen. What are the distances on the screen (from the unscattered slit image) of the three birghtest (first-order, n=1) hydrogen lines for red 657nm, blue-green 486nm, and violet 434nm.

    I do not even know where to begin to solve this equation. The help is much appreciated.
     
  2. jcsd
  3. Jun 1, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    (please use the homework template in future)

    what equations do you know that might be relevant?
     
  4. Jun 1, 2012 #3
    dsin(theta)=n(lambda)
     
  5. Jun 1, 2012 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    ok, now apply that equation to the figures in the question …

    what do you get? :smile:
     
  6. Jun 1, 2012 #5
    I dont know what to do with the theta, since it is not given. and would i say that 1/d=the 475 mm/lines?
     
  7. Jun 1, 2012 #6
    and the final units needs to be in cm
     
  8. Jun 1, 2012 #7

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    Personally, I'd do all the calculations in m and then, if demanded, change the final answer to cm.
     
  9. Jun 1, 2012 #8
    I have been trying everything under the sun and still can not get the answer right. i used the equation x=n(lambda)L/d
    L=2.8m
    Lambda= 657nm
    d=(475 lines/mm)^-1

    am I incorrect with that or no? Because the answer is still wrong for finding the distance between the slits.
     
  10. Jun 2, 2012 #9

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    show us your actual calculation and results :smile:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Diffraction grating question
Loading...