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Homework Help: Current, direction of flow and potential difference in a circuit

  1. Feb 23, 2010 #1


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    1. The problem statement, all variables and given/known data

    The question is 'Calculate the current in each of the three resistors in the circuit in Figure 4 and indicate the direction of current flow. What is the potential difference between A and B?'

    View attachment Qu 4.pdf

    2. Relevant equations

    Kirchhoff's first and second laws, Ohm's law

    3. The attempt at a solution

    I assigned arbitary directions to the circuit and using Kirchhoff's first and second laws I have worked out the current in each of the three resistors to be:

    i1 = 0.4A
    i2 = -0.2A
    i3 = 0.2A

    I then decided that the current i2 flows in the opposite direction to what I have marked, as it is negative.

    To work out the potential difference between A and B can I just use Ohm's law

    V = iR
    V = 0.2A x 10 [tex]\Omega[/tex]
    V = 2, so the potential difference between A and B is 2?

    Last edited: Feb 23, 2010
  2. jcsd
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