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Homework Help: Inductance problem

  1. Sep 11, 2008 #1
    inductance, flux, capacitance
    1. The problem statement, all variables and given/known data
    The magnetic field at one place on the earth’s surface is 55 μT in strength and tilted 60°
    down from horizontal. A 200-turn coil having a diameter of 4.0 cm and a resistance of 2.0 Ω
    is connected to a 1.0 μF capacitor rather than to a current meter. The coil is held in a
    horizontal plane and the capacitor is discharged. The coil is then quickly rotated 180° so that
    the side that had been facing up is now facing down. Afterward, what is the voltage across
    the capacitor? [Hint: use I=dq/dt

    2. Relevant equations
    LaTeX Code: \\Phi =ABcosLaTeX Code: \\theta
    I=LaTeX Code: \\Phi /L
    LaTeX Code: \\Phi =NLaTeX Code: \\Phi per coil

    3. The attempt at a solution
    ok wat i did was find flux per coil=LaTeX Code: \\pi r2BcosLaTeX Code: \\theta =3.45x10-8
    then flux=3.45x10-8*200=6.9x10-6=L(di/dt)=Q/C....
    but that cant be right coz i know the answer is 12V... can someone please help me, ive been on this for 4 or hours and its 3am almost... due in tomoz... plz someone help... 1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Sep 11, 2008 #2
    any ideas??
  4. Sep 11, 2008 #3
    plz im getting disparate here... well emf=|d[tex]\Phi[/tex]/dt|=L*di/dt=6.91x10-6... does not sound right at all!!!
    emf=IR=>I=emf/R=... oh id dunno plz!!
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