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JEE Main & Advanced Physics Electro Magnetic Induction Question Bank Faraday's and Lenz's Law

  • question_answer
      The magnetic flux linked with coil, in weber is given by the equation, \[\varphi =5{{t}^{2}}+3t+16\]. The induced emf in the coil in the fourth second is                                                              [Pb. PMT 2004]

    A)            10 V                                         

    B)            30 V

    C)            45 V                                         

    D)            90 V

    Correct Answer: A

    Solution :

                       \[|e|\,=\frac{d\varphi }{dt}=\frac{d}{dt}(5{{t}^{2}}+3t+16)=(10t+3)\]                    when \[t=3\sec ,\ {{e}_{3}}=(10\times 3+3)=33\ V\]                    when \[t=4\sec ,\ {{e}_{4}}=(10\times 4+3)=43\ V\]                    Hence emf induced in fourth second            \[={{e}_{4}}-{{e}_{3}}=43-33=10\ V\]


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