Chhattisgarh PMT Chhattisgarh PMT Solved Paper-2009

  • question_answer
    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 retentivity (so as to make a stronger magnet)  and  high  coercivity  (so  that magnetisation may not be wiped out easily). For electromagnet we prefer high saturated magnetism, low coercivity 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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