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!

Incident light angle brightness

  1. Feb 22, 2007 #1
    when light hits a surface at an angle. it is darker if it hits it at higher angle(facing away) than at a lower angle(facing towards). 1


    Is there a formula for the brightness.The relationship of angle to brightness does not look linear.


    http://www.vam.ac.uk/vastatic/microsites/1384_leonardo/animated_illustrations/view/?movie=light" [Broken]1
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Feb 23, 2007 #2

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The brightness would go like cos of the angle.
     
  4. Feb 23, 2007 #3
    Is this only because the greater the angle, the greater the surface area that the beam interacts with? Or are there other factors?
     
  5. Feb 24, 2007 #4

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    It is just that Intensity = Power/area
     
  6. Feb 24, 2007 #5

    robphy

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    There is also an inverse-square dependence, which is negligible if (for example) a point-like source is very far from the surface.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook