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!

Homework Help: Induced emf/current

  1. Feb 22, 2009 #1
    1. The problem statement, all variables and given/known data

    Resistance = R
    Radius = r
    Angle = theta
    B = 2cos(2t)
    Circular wire loop where magnetic field acts at theta degrees with respect to the normal of the wire loop.

    Find induced current and emf in wire loop. Find induced electric field at radial distance d from center of wire loop.

    2. Relevant equations

    [tex]\epsilon[/tex] = -d[tex]\Phi[/tex]/dt
    I = [tex]\epsilon[/tex]/R

    3. The attempt at a solution

    A = [tex]\pi[/tex]r[tex]^{}2[/tex]
    [tex]\epsilon[/tex] = d(BA)/dt
    = A dB/dt
    = [tex]\pi[/tex]r[tex]^{}2[/tex] d(2cos(2t))/dt
    = -4[tex]\pi[/tex]r[tex]^{}2[/tex] sin(2t) = induced emf (area not changing)

    Given a magnetic field B with a constraint of 2t for [tex]\omega[/tex]t, and no time, the answer must be with respect to t, correct? You can't use the frequency given by 2/2pi can you?

    i = [tex]\epsilon[/tex] / R
    i = -4[tex]\pi[/tex]r[tex]^{}2[/tex] sin(2t) / R

    Since I still don't know time I'm guessing I have to solve as a function of t?

    [tex]\epsilon[/tex] = dB/dt d/2 = -2sin(2t)d
    Last edited: Feb 22, 2009
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted