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!

Electric flux

  1. Mar 11, 2010 #1
    Why the electric flux [tex]\Phi[/tex] is defined as EAcos[tex]\theta[/tex]?

    I don't understand the part about cos[tex]\theta[/tex].....
  2. jcsd
  3. Mar 11, 2010 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

  4. Mar 11, 2010 #3


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi yaik! Welcome to PF! :smile:

    Imagine you want to know the flux of bugs flying horizontally along a road.

    If you count the number that go splat on your windscreen, then you'll collect less (in a given time) if the windscreen is tilted: the number will be greatest at 90º, and zero at 0º: it'll be proportional to cosθ. :smile:

    Mathematically, flux of a field E through a surface with area A is E.(Añ), where ñ is the unit vector normal (perpendicular) to the surface. :wink:
  5. Mar 12, 2010 #4
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook