Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Wavelenght, index of refraction and speed

  1. Feb 16, 2010 #1
    THe wavelength of a red helium-neon laser light in air is 632.8 nm.

    A) what is the frequency? ( i already figured this out to be 4.7 x 10^16)

    B) what is its wavelenght in glass that has an index of refraction of 1.50?( i do not know where to or if i have to plug in the refraction into an equation and if i do what equation do i use?)

    C) what is its speed in the glass? ( is this then related to question B? because i do not know how now to bring in v into the equation and what the equation is. i am just confuzed)
     
  2. jcsd
  3. Feb 16, 2010 #2
    [tex]n=\frac{\lambda_0}{\lambda}[/tex]

    [tex]\lambda_0[/tex] is the wavelength in air.

    Part c should be easy once you have part b.
     
  4. Feb 16, 2010 #3

    collinsmark

    User Avatar
    Homework Helper
    Gold Member

    Btw, you might want to double check that. If your units are Hz, I think you are a couple orders of magnitude off.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook