JEE Main & Advanced Physics Magnetism Question Bank Magnet and its Properties

  • question_answer
    If a magnet of length 10 cm and pole strength 40 A-m is placed at an angle of 45o in an uniform induction field of intensity 2 ´ 10?4 T, the couple acting on it is  [Pb. PMT 1999; MH CET (Med.) 1999]

    A)            0.5656 ´ 10?4 N-m              

    B)            0.5656 ´ 10?3 N-m

    C)            0.656 ´ 10?4 N-m                 

    D)            0.656 ´ 10?5 N-m

    Correct Answer: B

    Solution :

                       \[\tau =MB\sin \theta =\left( mL \right)B\sin \theta \]                      \[=(40\times 10\times {{10}^{-2}})\times 2\times {{10}^{-4}}\times \sin 45{}^\circ \]              \[=0.565\times {{10}^{-3}}N-m\]


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