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Homework Help: Magnetic Field and induced current

  1. Dec 22, 2004 #1
    Can anyone help me to do this problem. Thanks in advance.

    A closed wire loop in the form of a square of side 4.0cm is mounted with its plane horizontal. The loop has a resistance of 2.0*10^(-3) ohm. The loop is situated in the magnetic field of strength 0.7 T directed vertically downwards.
    When the field is switched off, it decreases to 0 at a uniform rate in 0.8s
    What is:
    a) The current induced in the loop.?
    b) The energy dissipated in the loop during the change in the magnetic field?
  2. jcsd
  3. Dec 22, 2004 #2
    What have you done so far? You have enough information to work out the EMF induced in the loop, so you can work out the current.
  4. Dec 22, 2004 #3


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    Science Advisor
    Homework Helper

    Here are some formulas that might help:
    [tex] U_{induced}=-\frac{\Delta \Phi_{mag}}{\Delta t} [/tex]
    [tex] \Phi_{mag}=:\vec{B}\cdot \vec{S} [/tex]
    [tex] I_{induced}=\frac{U_{induced}}{R} [/tex]
    [tex] W=U_{induced}I_{induced}t [/tex]


    PS.The problem is very easy.Hopefully u'll solve it by yourself...
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