JEE Main & Advanced Physics Electro Magnetic Induction Question Bank Mock Test - Electromagnetic Induction

  • question_answer
    A conducting rod PQ of length \[l\] = 2 m is moving at a speed of \[2\,m{{s}^{-1}}\] making an angle of \[30{}^\circ \] with its length. A uniform magnetic field B = 2 T exists in a direction perpendicular to the plane of motion. Then

    A) \[{{V}_{p}}-{{V}_{Q}}=8V\]

    B) \[{{V}_{p}}-{{V}_{Q}}=4V\]

    C) \[{{V}_{Q}}-{{V}_{P}}=8V\]

    D) \[{{V}_{Q}}-{{V}_{P}}=4V\]

    Correct Answer: B

    Solution :

    [b] Emf induced across the rod AB is \[e=\vec{B}.(\vec{\ell }\times \vec{v})=B\ell v\sin \theta =2\times 2\times 2\times \sin 30\]\[e=4V\] Free electrons of the rod shift towards right due to force \[q(\vec{v}\times \vec{B})\] Thus, end P is at higher potential Or \[{{V}_{P}}-{{V}_{Q}}=4\,V.\] Thus, choice (2) is correct.


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