2. Questions Bank
  3. 12th Class
  4. Physics
  5. Magnetism

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

  • question_answer
    A 2.5 m long straight wire having mass of 500 g is suspended in mid air by a uniform horizontal magnetic field B. If a current of 4 A is passing through the wire then the magnitude of the field is (Take \[g=10m{{s}^{-1}}\]):

    A) 0.5 T                            

    B) 0.6 T   

    C) 0.25 T                          

    D) 0.8 T

    Correct Answer: A

    Solution :

    (a) 0.5 T                                           Here,    \[m=500g=0.5\,kg,\,l=4\,A,\,l=2.5\,m\] As         \[F=IlB\,\sin \theta \] \[mg=IlB\,\sin \,90{}^\circ ,(\because \theta =90{}^\circ \,\,and\,\,F=mg)\]\[\therefore B=\frac{mg}{Il}=\frac{0.5\times 10}{4\times 2.5}=0.5T\]


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