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!

Faraday's law

  1. Jun 5, 2013 #1
    A magnetic field of B=0.5B0z^ is present when a loop with radius r is rotated around the y axis with angular velocity of w=9 rad/s. What is the induced emf?

    Well: flux = SB*dA = SBdAcosq(t) = Bcosq(t)SdA = 0.5B0*pi*r^2cosq(t)

    d(flux)/dt = 0.5B0*pi*r^2*-sinq(t)*dq(t)/dt = 0.5B0*pi*r^2*-sinq(t)*9.

    But I'm still stuck with the angle q which isn't given to me... What should I do?
     

    Attached Files:

  2. jcsd
  3. Jun 5, 2013 #2
    The attachment shows ##B=(1/2)B_0 t^2## and you use ##B=(1/2)B_0##.

    And what is S?
     
  4. Jun 5, 2013 #3
    I think you are mostly correct. However, what should the argument of cosq(t) be? could it be cosq(9t)?
     
  5. Jun 5, 2013 #4
    The first magnetic field is from another part of the question - if you look at the bottom you'll see the field I wrote here. S in the sign of integration ∫, forgot about the operators here :P
     
  6. Jun 5, 2013 #5
    You're right! It's analoug to x=vt for constant speed movement... thanks!
     
  7. Jun 5, 2013 #6
    Ah ok but I don't think you need to deal with integrals here.

    You know ##\phi=\vec{B}.\vec{A}##. The direction of A is perpendicular to plane of ring. When the area vector rotates by an angle ##\theta##, evaluate ##\phi##.

    PS: Can you post the answer so that I can check my working?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Faraday's law
  1. Faraday's law (Replies: 1)

  2. Faraday's Law (Replies: 9)

  3. Faraday's law (Replies: 6)

  4. Faraday's Law (Replies: 1)

  5. Faraday's Law (Replies: 2)

Loading...