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!

Torque on Current Loops

  1. Mar 2, 2007 #1
    1. The problem statement, all variables and given/known data
    The 10-turn loop of wire shown in the figurelies in a horizontal plane, parallel to a uniform horizontal magnetic field, and carries a 2.0 A current. The loop is free to rotate about a nonmagnetic axle through the center. A 50 g mass hangs from one edge of the loop.

    2. Relevant equations
    Torque = u * B
    Torque = (I*A) B

    3. The attempt at a solution
    Ive tried all sorts of things I konw that I is 2.0 A and A is .1 * .05 so that gives .01 * B = Torque and Ive set torque equal to just the F of the weight times the radius and diameter and Ive also tried doubling the F because the force down on both sides. No matter what Ive tried it doesn't seem to work. Answers that I have gotten are 1.225. 2.45, 4.9, and .6125 so if you try this problem and get those they are wrong. Thanks for the help.

    Attached Files:

  2. jcsd
  3. Mar 3, 2007 #2
    If there are 10 turns in the loop, wouldn't you use the equation that incorporates the # of turns?

    As far as I know, the 2nd equation you stated holds true for rectangular loops (I can't see your attachment so I don't really know what the problem set up is).

    Additionally, if the loops is parallel to the magnetic field...what would sin(theta) be?
    Last edited: Mar 3, 2007
  4. Mar 3, 2007 #3
    I can't find any equations in my book for turns in the loop so if you could help me out with that Id appriciated it and I was wondering that myself as for the picture it is set up as a rectangular loop so I wasn't sure that the turns ment anything and wouldn't it make the sin of theta 90 degrees?
  5. Mar 3, 2007 #4
    For any other loop that is not a rectangle, torque=NIABsin(theta), where N=# of turns.
  6. Mar 3, 2007 #5
    ok got it thanks for the help.
  7. Dec 17, 2008 #6
  8. Dec 17, 2008 #7
    Did anybody come up with an answer for this question?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Torque on Current Loops