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!

Induced EMF, finding current

  1. Mar 23, 2010 #1
    1. The problem statement, all variables and given/known data

    A coil with 253 turns of wire, a total resistance of 28 Ohms, and a cross-section area of 0.36m^2 is positioned in a plane perpendicular to the field of a powerful electromagnet.
    What average current is induced in the coil during the 0.33s that the magnetic field drops from 2.2T to 0.0T? Answer in units of A.


    2. Relevant equations

    E = BA / t
    V = IR

    3. The attempt at a solution

    EMF = Change in B * Area / time
    = (2.2 * .36) / .33

    I plug that into V = IR

    V = IR
    [(2.2 * .36) / .33] = I * 28 Ohms
    I = [(2.2 * .36) / .33] / 28 = 0.0857142857A

    However I get the wrong answer.
    I think it has something to do with the 253 coils of wire but I'm not sure.
    Any help is appreciated.
     
  2. jcsd
  3. Mar 23, 2010 #2
    Yes, the emf you calculate is induced in each coil of wire, so the total flux linkage at the start is BAN where N is the nuber of turns.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Induced EMF, finding current
Loading...