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Homework Help: Electricity homework problem

  1. Apr 22, 2012 #1
    1. The problem statement, all variables and given/known data

    (i) What is the strength and direction of the force per unit length acting on a straight conductor carrying an electrical current, I, in a magnetic field, B?

    (ii) The figure below shows a square frame of aluminium set at an angle θ to the direction of a strong static magnetic field, B, parallel to the x-axis (the y-axis is vertical). The frame has sides of length L and the arms have cross-sectional area A, with L >> √A. Write down expressions for the electrical resistance (for currents flowing around the frame) and the total mass if the density and conductivity of aluminium are ρ and σ respectively.

    (iii) left out for the moment

    2. Relevant equations

    3. The attempt at a solution

    (i) F = B x Il,
    so F/l = BIsinφ, where φ is the angle between the direction of force and the length of the conductor and the force acts in a direction which is perpendicular to the magnetic field and the length of the conductor.

    (ii) Electrical resistance R = L/σA

    Total mass = ρV = ???

    Any comments would be greatly appreciated.

    Attached Files:

    Last edited: Apr 22, 2012
  2. jcsd
  3. Apr 22, 2012 #2
    Re: Electricity

    Well, V=LA.
  4. Apr 22, 2012 #3
    Re: Electricity

    Well, I know that but the problem is part of the frame is missing, so don't know how to take that into account.
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