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!

Application of the properties of light

  1. Jan 21, 2015 #1
    1. The problem statement, all variables and given/known data
    Light with wavelengths of 520 nm and 630 nm passes through a diffraction grating that contains 6000lines/cm.
    a) Sketch a diagram of the image produced from m = 0 to m = 2. Label the order of each fringe.
    b) Calculate the angles for the first and second order maxima that would appear on the screen.
    c) What is the lowest value of m for which the 520 nm line no longer exists? Justify your answer.
    d) Compare the appearance of the fringe at m=0 with all the others.

    2. Relevant equations
    SinΘ= mΛ/d
    d= 1m/6.0x10^5lines
    d=1.67x10^-6m/line


    3. The attempt at a solution
    I am taking a learn at home course and this material is very new to me. I don't want to be told answers I'm just having a lot of difficulty grasping the entire concept of light if I'm being honest.
    I have used the equation to solve for b and c.
    The issue I'm having, perhaps I am over thinking it, is that I do not know how to sketch the diagram of the maxima and fringes. How am I to know the distances between fringes and the maxima? I tried to look through other equations in previous chapters but they require another variable, L, which I do not have. Of course without the sketch I cannot solve D.
    I was just hoping someone could help guide me into figuring it out on my own.
     
    Last edited by a moderator: Jan 21, 2015
  2. jcsd
  3. Jan 21, 2015 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Just draw what you'd expect to see on a screen. If you don't know what that is, you should look for some pictures of diffraction patters online.

    That's what the equations are for.
    You may want to use a little geometry - but your notes should have that done for you.
    However you don't need to know to draw a sketch. You just need to illustrate the important points.

    You don't need to be so exact. It's only a sketch to give the idea.
     
  4. Jan 21, 2015 #3

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    All distances will scale in the same way with L. For a sketch, you don't need exact distances, the scale can be arbitrary.
     
  5. Jan 21, 2015 #4

    BvU

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Hello Paige, welcome to PF :)

    This is a physics subject that can be nicely supported with internet stuff like here
    Google double-slit interference to find a ton more sites. Wikipedia has a nice animated picture.
    Hyperphysics is a good site too.
     
  6. Jan 21, 2015 #5
    I know what diffraction patterns look like but to sketch a diffraction pattern with two different wavelengths and label both maxima is what is throwing me off.
    Am I on the right track if I use my calculations for part B to help me locate the m0-2 on the sketch? As the angles for the first and second orders are different could I assume that would affect their distance to the central maximum? the 520nm wavelength, for example, is 18degrees at m1 where as the 630nm wavelength is 22 degrees.
    So, to sketch I would assume that means the 520nm would have a m1 closer to the central maximum?
    Of course doing this I feel the sketch is very vague and wont be scaled correctly.
     
  7. Jan 21, 2015 #6

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    You can do it for either one?
    The combined pattern is the sum of the two by themselves.
    Have you seen the diffraction pattern for white light?
     
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: Application of the properties of light
  1. Properties of light? (Replies: 2)

Loading...