Home Forums Exams and revision Definition of magnetic flux VCE 2023 MC Q.6

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  • Mt Alexander College
    Participant
    Post count: 1

    I have question about the suggested answer by Vicphysics.

    When I was young, I learned: EMF = – d (PHI) /dt
    PHI(uppercase) is the magnetic flux pass through the “coil” and PHI is also equal to N*phi, where phi(lower case) is the flux through individual loop. Therefore, EMF= -N d(phi)/dt

    In the VCE question, it seems they have distinguish the words “coil” and “loop”. And the question, it asked “magnetic flux through the coil” not loop. Therefore, I suggest the answer should be B instead of A.

    For me, it seems my definition of flux is slightly different from Australia although the physics concepts are the same.

    There is a typo in the suggested solution, missed the square.

    Man LAM
    Laboratory technician
    (Mt Alexander College)

    Barbara McKinnon
    Participant
    Post count: 2

    Dear Man,
    Thanks for your comment. This is a question that comes up quite often in discussion.
    I don’t think the upper case PHI notation is helpful or physically correct. There are not N lots of flux. The flux is a measure of the intensity of the field passing through a surface area. The material bounding the surface area is independent of the concept of flux. Maxwell’s equations tell us that a changing magnetic field produces an electric field. This means that if the area through which a magnetic field passes is bounded by a conducting loop and the flux through the loop changes, then an electric field and corresponding EMF is experienced at all points on the loop and, if the loop is continuous a current will flow. More loops, means more points on conductor experiencing an electric field, and hence more current.

    Sorry to take so long to notice your post!
    Regards,
    Barbara

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