MGIMS WARDHA MGIMS WARDHA Solved Paper-2011

  • question_answer
    The earth's magnetic induction at a certain point is \[7\times {{10}^{-5}}\] Wb/m2. This is to be annulled by the magnetic induction at the centre of a circular conducting loop of radius 5 cm. The required current in the loop is

    A)  0.56 A                                  

    B)  5.6 A

    C)  0.28 A                                  

    D)  2.8 A

    Correct Answer: B

    Solution :

                     Magnetic field at the centre of loop. \[B=\frac{{{\mu }_{0}}i}{2r}\] \[\therefore \]  \[i=\frac{2Br}{{{\mu }_{0}}}\] \[=\frac{2\times 7\times {{10}^{-5}}\times 5\times {{10}^{-2}}}{4\pi \times {{10}^{-7}}}\] \[=\frac{2\times 7\times {{10}^{-5}}\times 5\times {{10}^{-2}}}{4\times \frac{22}{7}\times {{10}^{-7}}}=5.6A\]


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