Haryana PMT Haryana PMT Solved Paper-2009

  • question_answer
    44.          If the B-H curves of two samples of P and Q of   iron are as shown below, then which one of the following statements is correct?  

    A)  Both P and Q are suitable for making permanent magnet

    B)  P is suitable for making permanent magnet and Q for making electromagnet

    C)  P is suitable for making electromagnet and Q is suitable for permanent magnet

    D)  Both P and Q are suitable for making electromagnets

    Correct Answer: B

    Solution :

                    For permanent magnet we prefer a material with high retentively (so as to make a stronger magnet)  and high coercively  (so  that magnetisation may not be wiped out easily). For electromagnet we prefer high saturated magnetism, low coercively and least possible area of hysteresis loop so that electromagnet develops  high  magnetisation,  is  easily demagnetised   and   energy  loss   in   a magnetisation cycle is least. Therefore, P is suitable for making permanent magnet and Q for making electromagnet. .


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