Results 1 to 7 of 7

Thread: Help!!!

  1. #1
    OptiBoard Novice
    Join Date
    Jan 2022
    Location
    Alexandria, Va
    Occupation
    Dispensing Optician
    Posts
    1

    Confused Help!!!

    Hi Everyone! I'm new to this forum. I'm studying for my ABO certification, I'm currently struggling with the Snell's Law formula. Can someone explain in simpler way for me to understand?

  2. #2
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
    Join Date
    Dec 2004
    Location
    At a position without dimension...
    Occupation
    Dispensing Optician
    Posts
    4,948
    Welcome to Optiboard!

    This may help from a long ago post by the late great Chris Ryser found using the search box. Post #3

    https://www.optiboard.com/forums/sho...=Snell%27s+Law

    There still is no "easy" way unfortunately.

  3. #3
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    8,499
    Here's a good conceptual.

    Picture light waves as ziggly things like vibrating string, but very tiny.

    When light is ziggling through space, it's going as fast as it can, because of no resistance (almost. Shut up everyone else with solar wind and nebula dust.)
    When light is ziggling through air, it slows down a bit.
    Man, does it really slow down through diamond!

    So a straight shot of light will go from "speed of light in a vaccuum = c" to slower "speed of light in vegetable oil = something else". And if you compare the two, you'll get the "refractive index" of the "something else":

    speed of light in something else / speed of light in vaccuum = 1.59 (proving polycarbonate is made of vegetable oil? Ha.)



    But light doesn't always go into a new goo in a straight shot. What if it enters the diamond at an angle? Then what? Well, it slows down, but since it enters at an angle, the first part of the vibrating string gets slowed down first and a nanopicosecond later, the trailing edge of the string gets slowed down last, causing a bend in the direction.


    So the formula is just ratios:

    index of new goo/index of original goo is the index of refraction
    the angle of the incidence is the second factor.

    So Snell's law is simply: what's the angle light emerges from the change in goo? Well, its the angle it went into the goo, but multiplied by the ratio of the refractive indices.

  4. #4
    Master OptiBoarder OptiBoard Silver Supporter lensmanmd's Avatar
    Join Date
    Oct 2016
    Location
    Maryland
    Occupation
    Optical Wholesale Lab (other positions)
    Posts
    1,105
    DRK is the new Goo Goo Doll.
    Go ahead with your bad self, DRK!
    I bend light. That is what I do.

  5. #5
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
    Join Date
    Dec 2004
    Location
    At a position without dimension...
    Occupation
    Dispensing Optician
    Posts
    4,948
    Quote Originally Posted by lensmanmd View Post
    DRK is the new Goo Goo Doll.
    Go ahead with your bad self, DRK!
    Ziggly Stardust playing guitar left handed.

  6. #6
    Master OptiBoarder optical24/7's Avatar
    Join Date
    May 2006
    Location
    Down on the Farm
    Occupation
    Dispensing Optician
    Posts
    5,546
    Quote Originally Posted by drk View Post
    Here's a good conceptual.

    Picture light waves as ziggly things like vibrating string, but very tiny.

    When light is ziggling through space, it's going as fast as it can, because of no resistance (almost. Shut up everyone else with solar wind and nebula dust.)
    When light is ziggling through air, it slows down a bit.
    Man, does it really slow down through diamond!

    So a straight shot of light will go from "speed of light in a vaccuum = c" to slower "speed of light in vegetable oil = something else". And if you compare the two, you'll get the "refractive index" of the "something else":

    speed of light in something else / speed of light in vaccuum = 1.59 (proving polycarbonate is made of vegetable oil? Ha.)



    But light doesn't always go into a new goo in a straight shot. What if it enters the diamond at an angle? Then what? Well, it slows down, but since it enters at an angle, the first part of the vibrating string gets slowed down first and a nanopicosecond later, the trailing edge of the string gets slowed down last, causing a bend in the direction.


    So the formula is just ratios:

    index of new goo/index of original goo is the index of refraction
    the angle of the incidence is the second factor.

    So Snell's law is simply: what's the angle light emerges from the change in goo? Well, its the angle it went into the goo, but multiplied by the ratio of the refractive indices.

    When did they legalize pot in Ohio?…

  7. #7
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
    Join Date
    Dec 2006
    Location
    Rossford, Ohio
    Occupation
    Dispensing Optician
    Posts
    1,602
    It's only legal with a prescription that I don't think OD's can write ?

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •