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

Question about light's speed

  1. Jun 17, 2004 #1
    how does air/glass/water slow down light?
     
  2. jcsd
  3. Jun 17, 2004 #2
    It doesn't really.. light speed remains the same. However, photons are absorbed and re-emitted on the way through the medium and it is the time that this takes that makes them appear to travel slower.
     
  4. Jun 18, 2004 #3
    Why are they absorbed and re-emitted? How?
     
  5. Jun 18, 2004 #4
    Basically photons carry a certain amount of energy with them. Electrons bound to an atom (not free electrons) will be able to absorb this energy and fly up an energy level or two. When they go back down they will emit a photon.

    Question, does the index of refraction reflect colors of different wavelengths differently because the latice structure of the compound? Also, how come there is no light that goes straight, or is there just a tiny amount due to probability of not being scattered.
     
  6. Jun 18, 2004 #5

    Gza

    User Avatar

    Light moves "straight" through a vacuum.
     
  7. Jun 18, 2004 #6
    Why is it then re-emitted in the same (or opposite, whatever you want) direction that it has been absorbed?
     
  8. Jun 18, 2004 #7

    selfAdjoint

    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    Conservation of momentum.
     
  9. Jun 18, 2004 #8

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Question about light's speed
Loading...