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!

Snell's Law coursework problem

  1. Feb 4, 2006 #1
    Hello All,


    My child is a student is Florida. She is 14 years old and is enrolled in a Physics class. I was wondering if you guys oculd help me with this question (I am not Physics major)

    [​IMG]

    Based on the diagram above, did the light bend toward or away from the normal as it passed from air into the top of the glass plate?

    Thanks in advance,
    Rachel.
     
    Last edited: Feb 4, 2006
  2. jcsd
  3. Feb 4, 2006 #2
    The Diagra, has now been edited :)
     
  4. Feb 4, 2006 #3

    Ouabache

    User Avatar
    Science Advisor
    Homework Helper

    Welcome RoRo to Physics Forums!! There are young & old here, so please encourage you child to join us, she will undoubtedly find lots of useful and interesting topics across this forum.

    The first thing is, she needs to describe what she has thought so far, about the question(s), then we can proceed to steer her in a successful direction. (hint: the answer to this question can be seen in your diagram)
    Be sure to read this thread so you will know what is expected of people asking homework questions.

    Here is a reference, to get you started.
     
    Last edited: Feb 4, 2006
  5. Feb 5, 2006 #4
    Thanks a lot for responding. This wasn't really a homework question. It was a review and reflect problem in her text book. Okay she told me to tell you that she knows that "When light slows down, it bends towards the normal, and when it speeds up it bends away from the normal."

    She says that what she can't figure out is whether the light rays are speeding up in this diagram...
     
  6. Feb 5, 2006 #5

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I'll admit that the diagram isn't very good, I can't tell which way the ray is bending. However, you can figure it out logically. Does you daughter know why the light slows down or speeds up?
     
  7. Feb 5, 2006 #6
    She says it depends of the refractive index of the period, or so she thinks.
     
  8. Feb 5, 2006 #7

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    So does glass have a higher or lower refractive index than air?
    Just looking at the diagram again, you can tell whether the ray bent towards or away from the normal, tell her to look at the ray after it exited the block.
     
  9. Feb 5, 2006 #8
    "The galss has a higher refractive index than the air" according to her. She also says that she thinks the ray bends away from the 1st normal, but it bends towards the 2nd.
     
  10. Feb 5, 2006 #9

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    That's the wrong way round. Does she now the mathematical form of snell's law?
     
  11. Feb 5, 2006 #10
    No, she doesn't.
     
  12. Feb 5, 2006 #11
    She just mentioned something about the co sine of the refractive index over something. She is not 100% sure of the matchematical form. Sorry.
     
  13. Feb 5, 2006 #12

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Okay, when refraction occurs, the ray leaving the block must be parallel to the ray entering the block. See if that helps.
     
  14. Feb 5, 2006 #13

    Ouabache

    User Avatar
    Science Advisor
    Homework Helper

    Sorry I didn't reply sooner. Just got a chance to see your post again..
    Since you know that the glass has a higher refractive index than air, take another look at the first figure in the reference I gave you. It shows a clear direction of the bending relative to the normal. (normal is a perpendicular line or plane with respect to something. In this case with respect to the surface of the glass). It should clarify what you and Hootenanny have discussed.

    Just for fun, can you think of an example in nature, where this phenomenon may occur?:rolleyes:
     
    Last edited: Feb 6, 2006
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Snell's Law coursework problem
  1. Snells Law problems. (Replies: 10)

  2. Snell's Law Problem (Replies: 1)

  3. Snell's Law Problem (Replies: 3)

  4. Snell's Law problem (Replies: 12)

Loading...