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Homework Help: A coil of wire is connected to an uncharged capacitor in a magnetic field

  1. Jun 7, 2007 #1
    a coil of wire is connected to an uncharged capacitor in a magnetic field....

    1. The problem statement, all variables and given/known data
    A 10-turn coil of wire having a diameter of 1.0 cm and a resistance of 0.20 ohms is in a 1.0 mT magnetic field
    with the coil oriented for maximum flux. The coil is connected to an uncharged 1.0 microFarad capacitor rather than to a current meter. The coil is quickly pulled out of the magnetic field. Afterward, what is the voltage across the capacitor?
    Hint: Use I=dq/dt to relate the net change of flux to the amount of charge that flows to the capacitor.

    2. Relevant equations
    potential difference = -L dI/dt, where L is the inductance
    magnetic field, B = Uo NI/l
    total magnetic flux = N (magnetic field for each turn) = N (Area)(B) = (Uo N^2 A I) / l
    I = V/R
    induced emf = |change in magnetic flux/change in time|
    V = Q/C

    3. The attempt at a solution
    Voltage across the capacitor initially is 0 V, since capacitor is uncharged.
    I found the total flux to be 7.85 x 10^-7 Wb.
    The changing flux induces an emf.

    I'm really stuck here. Can someone please help me? Thanks :)
  2. jcsd
  3. Jun 8, 2007 #2
    no time is given? if you're given a time then you have [tex]\frac{d\phi _B}{dt}[/tex] and a voltage
  4. Jun 8, 2007 #3
    No time is given.
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