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!

Magnetic Field Protractor

  1. Apr 11, 2016 #1
    1. The problem statement, all variables and given/known data

    Screenshot 2016-04-11 at 6.png

    2. Relevant equations

    R = ρ (l/A)
    I = ε/R
    s = rθ
    Magnetic flux = Integral(B ⋅ dA)

    3. The attempt at a solution

    I managed to solve parts (a) and (b) independently. Here is my work for those two parts:


    My real issue is with part (c) which uses the answers from (a) and (b). I have absolutely know idea how to solve part c, except that it involves in some way the formula Magnetic flux = Integral(B ⋅ dA)
  2. jcsd
  3. Apr 11, 2016 #2


    User Avatar
    Homework Helper
    Gold Member

    Be careful with converting mm2 to m2.

    So far, you have not mentioned the basic law of electromagnetism that accounts for the induced current in the circuit.
  4. Apr 12, 2016 #3
    Yes, You're right. That law goes as follows:

    ε = - the rate of change of flux (sorry I do not know how to write this in the proper notation)

    And the induced current is found, simply, through Ohm's law: ε = iR

    So how can I, with this, go about part (c)?
  5. Apr 12, 2016 #4


    User Avatar
    Homework Helper
    Gold Member

    How do you find the rate of change of a quantity. What mathematical operation is involved?
  6. Apr 12, 2016 #5
    Take the derivative. So I can take the derivative of part (b). But theta needs to be expressed in terms of the time, t?
  7. Apr 12, 2016 #6


    User Avatar
    Homework Helper
    Gold Member

  8. Apr 12, 2016 #7
    Thank you!
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: Magnetic Field Protractor
  1. Magnetic Field (Replies: 2)

  2. Magnetic field (Replies: 2)

  3. Magnetic fields (Replies: 3)

  4. Magnetic Fields (Replies: 4)