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12th Class Physics Electro Magnetic Induction Question Bank MCQ - Electromagnetic Induction

  • question_answer
    A square loop of side l, resistance R is placed in a uniform magnetic field B acting normally to the plane of the loop. If we attempt to pull it out of the field with a constant velocity v, then the power needed is:

    A) \[BRlv\]            

    B) \[\frac{{{B}^{2}}{{l}^{2}}{{v}^{2}}}{R}\]

    C) \[\frac{B{{l}^{2}}{{v}^{2}}}{R}\]                

    D) \[\frac{Bvl}{R}\]

    Correct Answer: B

    Solution :

    (b) \[\frac{{{B}^{2}}{{l}^{2}}{{v}^{2}}}{R}\] Power, \[P=Fv=ilBv=\left( \frac{Bvl}{R} \right)lBv=\frac{{{B}^{2}}{{l}^{2}}{{v}^{2}}}{R}\]


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