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

  • question_answer
    The magnetic flux through a coil perpendicular to its plane and directed into paper is varying according to the relation \[\phi =(2{{t}^{2}}+4t+6)mWb\]. The emf induced in the loop at \[t=4s\] is:

    A) 0.12 V        

    B) 2.4 V

    C) 0.02 V                          

    D) 1.2 V

    Correct Answer: C

    Solution :

    (c) 0.02 V                              Give, \[\phi =(2{{t}^{2}}+4t+6)mWb\] As \[\varepsilon =\frac{d\phi }{dt}=\frac{d}{dt}(2{{t}^{2}}+4t+6)\times {{10}^{-3}}\]             \[=(4t+4)\times {{10}^{-3}}V\] At \[t=4\,\,s,\,\,\varepsilon =(4\times 4+4)\times {{10}^{-3}}V\]             \[=20\times {{10}^{-3}}V=0.02\,V\]


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