12th Class Physics Magnetism Question Bank MCQ - Moving Charges and Magnetism

  • question_answer
    A circular loop of radius 3 cm is having a current of 12.5 A. The magnitude of magnetic field at a distance of 4 cm on its axis is:

    A) \[5.65\times {{10}^{-5}}T\]                  

    B) \[5.27\times {{10}^{-5}}T\]

    C) \[6.54\times {{10}^{-5}}T\]                  

    D) \[9.20\times {{10}^{-5}}T\]

    Correct Answer: A

    Solution :

    (a) \[5.65\times {{10}^{-5}}T\]                         \[B=\frac{{{\mu }_{0}}I{{R}^{2}}}{2{{({{R}^{2}}+{{x}^{2}})}^{3/2}}}\] Here,      \[l=12.5\,A,\,R=3\,cm=3\times {{10}^{-2}}m\]             \[x=4\,cm=4\times {{10}^{-2}}m\] \[\therefore B=\frac{4\pi \times {{10}^{-7}}\times 12.5\times {{(3\times {{10}^{-2}})}^{2}}}{2{{[{{(3\times {{10}^{-2}})}^{2}}+{{(4\times {{10}^{-2}})}^{2}}]}^{3/2}}}=5.65\times {{10}^{-5}}T.\]


You need to login to perform this action.
You will be redirected in 3 sec spinner