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!

Work done by rectangular wire loop with current in magnetic field

  1. Oct 25, 2011 #1
    1. The problem statement, all variables and given/known data

    A rectangular wire loop of height h and width w, centered on the origin, carries current I in the direction shown in the figure. The angle between the positive x-axis and the plane of the loop is θ, defined as shown in the figure below. (When θ = 0 the loop lies in the x-z plane.) This entire region of space is filled with a uniform external magnetic field B pointing in the +x direction.

    http://i.imgur.com/4V960.png

    4V960.png

    Part A
    The magnitude of the work, |W|, involved in the rotation of the loop from θ = 0° to θ = 60° is:
    (a) |W| = 9.09 × 10-5 J Correct Answer
    (b) |W| = 2.37 × 10-4 J
    (c) |W| = 4.25 × 10-4 J
    (d) |W| = 5.87 × 10-4 J
    (e) |W| = 8.13 × 10-4 J

    Part B
    When the loop rotates from θ = 0° to θ = 60°, the external magnetic field
    (a) does no work on the loop.
    (b) does positive work on the loop. Correct Answer
    (c) does negative work on the loop.


    2. Relevant equations

    U= - dipole moment B cos(theta)


    3. The attempt at a solution

    For part A,
    I tried

    -( I * Area * B * cos(60)) - (-( I * Area * B * cos(0))) , however, it is wrong answer.

    For part B,
    I am confused about the work done by field (W) and the energy (U), what is difference?
    How do I know a work is positive or negative in this case?

    Thanks!
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

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



Similar Discussions: Work done by rectangular wire loop with current in magnetic field
Loading...