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WB JEE Medical WB JEE Medical Solved Paper-2010

  • question_answer
    The magnetic flux through a loop of resistance \[10\,\Omega \] is given by \[(o|=5{{t}^{2}}-4t+1\,Wb).\]How much current is induced in the loop after 0.2 s?

    A)  0.4 A                                    

    B)  0.2 A

    C)  0.04 A                  

    D)  0.02 A

    Correct Answer: B

    Solution :

                     The flux is given by \[\text{o }\!\!|\!\!\text{ =5}{{\text{t}}^{2}}-4t+1.\] The emf induced in the resistance would be equal to \[e=-\frac{d\text{o }\!\!|\!\!\text{ }}{dt}=10t-4.\] Thus, the current induced in the loop is equal to \[i=\frac{e}{R}=-\left( \frac{10t-4}{10} \right)\]at \[t=0.2s,\]we have \[i=-\left( \frac{10\times 0.2-4}{10} \right)=\frac{2}{10}=0.2A\]


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