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NEET-XII-Physics

38: Electromagnetic Induction

with Solutions - page 3
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  • #8
    A rod AB moves with a uniform velocity v in a uniform magnetic field as shown in figure.
    (a) The rod becomes electrically charged.
    (b) The end A becomes positively charged.
    (c) The end B becomes positively charged.
    (d) The rod becomes hot because of Joule heating.
    Figure
    digAnsr:   b
    Ans : (b) The end A becomes positively charged.
    Due to electromagnetic induction, emf e is induced across the ends of the rod. This induced emf is given by
    `` e=Bvl``
    The direction of this induced emf is from A to B, that is, A is at the higher potential and B is at the lower potential. This is because the magnetic field exerts a force equal to `` qvB`` on each free electron where q is `` -``1.6 × 10-16 C. The force is towards AB by Fleming's left-hand rule; hence, negatively charged electrons move towards the end B and get accumulated near it. So, a negative charge appears at B and a positive charge appears at A.
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