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!

Finding Magnetic Field from a Box

  1. Apr 9, 2015 #1
    1. The problem statement, all variables and given/known data
    A uniform magnetic field exists in a cubic volume of space with a
    50-mm side length.
    If the magnetic energy stored in this volume is
    19J , what is the magnetic field magnitude?
    (This is all the information I got. Been a bad week for since it just seem information for my homework is missing)

    2. Relevant equations
    This is where things are a little shaky. 0Al

    UB=1/2*B^2/μ

    3. The attempt at a solution
    Taking the length I used it to find the area of the cube. Which is what I take A to be, which I find weird considering I needed l as well.
    Setting it up I got

    (19*2*4piE-17)/(0.015)(5E-4) = B^2

    B = 2.51E-5 T
     
  2. jcsd
  3. Apr 9, 2015 #2
    I believe the equation you started with is the energy density, not just the Energy (check the units)

    [itex]\frac{U}{Volume of cube} = \frac{1}{2} \frac{B^2}{\mu}[/itex]
     
  4. Apr 9, 2015 #3
    actually, it looks like you did divide by the volume in your calculation, but the volume of the cube should just be (side length)^3.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted