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Homework Help: Mutual Induction of a solenoid and a coil

  1. Oct 30, 2011 #1
    1. The problem statement, all variables and given/known data

    A single-turn circular loop of radius R = 0.235 m is coaxial with a long 1780 turn solenoid of radius 0.0435 m and length 0.850 m, as seen in the figure below. The variable resistor is changed so that the solenoid current decreases linearly from 6.12 A to 1.46 A in 0.230 s. Calculate the induced emf in the circular loop. (The field just outside the solenoid is small enough to be negligible.)

    2. Relevant equations

    M=N*∏*μ0*n*r^2

    Vind = - N*∏*μ0*n*r^2 * di/dt

    di/dt=(1.46-6.12)/0.23

    3. The attempt at a solution

    I used mutual inductance equ to find the potential difference induced

    N is 1780, n=N/length, r=0.0435

    but I still can't get the correct answer. I don't know where I did wrong here. Does anybody help me to find the answer? Thank you
     

    Attached Files:

  2. jcsd
  3. Oct 30, 2011 #2
    Does anyone can help me?
     
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