1. Not finding help here? Sign up for a free 30min 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!

Why Cos is used here

  1. Jun 20, 2009 #1
    http://www.berkeleyscience.com/maxwells.htm

    """""When a conductor (a wire) is placed in an electric field, the field may induce a voltage in the conductor. The diagram shows an electric field in the x direction with magnitude E. If the conductor is perpendicular to the E field, there is no induced voltage. If the conductor is aligned with the E field, the induced voltage is E·l where l is the length of the wire. If the angle between the E field and the wire is θ then the induced voltage is E·cos(θ)·l."""

    ^^ this is quoted from the link i just gave ^^
    It is with reference to this image here : http://www.berkeleyscience.com/images/efield.jpg

    Now I am curious why Cos is used when determining the induced voltage, that's all i am curious about. Why not Sin? How would you determine to use Cos? Please can you help me in laymans terms because I am only beginning Trig properly
     
  2. jcsd
  3. Jun 20, 2009 #2

    Astronuc

    User Avatar

    Staff: Mentor

    The maximum voltage is induced when the E-field vector points along the conductor. When the E-field is at some angle, then it is the 'projection' or component of the E-field vector parallel to the conductor that causes the voltage.

    Think about - what is the significance of the cos and the angle between the hypotenuse and one leg.
    http://hyperphysics.phy-astr.gsu.edu/hbase/ttrig.html

    If one was interested in the projection or component of the E-field in the transverse direction to the conductor, then one would used the sin. But the transverse E-field would not be so significant here, although it would produce a tranverse voltage across the conductor, as a opposed to along the conductor.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Why Cos is used here
Loading...