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Force, current and Electric Field: How a motor rotates

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    Hi, a teacher gave me a question from a edexcel past paper A2 unit 4 and i am having troubles understanding how force, current and field works on one question:

    http://www.edexcel.com/migrationdocu...e_20110127.pdf

    Question 13, A and B

    I don't understand mark scheme, so could any prove help. I'll appreciate it!
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    If you could show us the mark scheme and state what it is you don't understand it would help us to answer your question.
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    (Original post by Stonebridge)
    If you could show us the mark scheme and state what it is you don't understand it would help us to answer your question.
    Q13 a and b:http://www.edexcel.com/migrationdocu...s_20110309.pdf
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    It might help if you indicate which part of the mark scheme you have a problem with.

    In any case, without seeing the mark scheme, this is how I'd answer the question;

    The coil turns due to the motor effect; since current is flowing through the coil and the coil is placed in a magnetic field, then there is a force acting on the coil. Using Fleming's left hand rule, we can say that the length of coil DC will have a vertical force acting up, and the length of coil BA will have a vertical force acting down, hence rotating the coil anti-clockwise. I would then draw arrows on the diagram indicating the direction and location of those forces.
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    (Original post by Rysm)
    It might help if you indicate which part of the mark scheme you have a problem with.

    In any case, without seeing the mark scheme, this is how I'd answer the question;

    The coil turns due to the motor effect; since current is flowing through the coil and the coil is placed in a magnetic field, then there is a force acting on the coil. Using Fleming's left hand rule, we can say that the length of coil DC will have a vertical force acting up, and the length of coil BA will have a vertical force acting down, hence rotating the coil anti-clockwise. I would then draw arrows on the diagram indicating the direction and location of those forces.
    Very much appreciated. I have a better understanding thanks.

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Updated: June 19, 2012
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