1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Kirchoff's Law question

  1. Jan 16, 2008 #1
    1. The problem statement, all variables and given/known data
    determine which way the current goes

    2. Relevant equations
    kirchoff's current law

    3. The attempt at a solution

    i say that it is moving away because if i say its positive going into element1 then since its negative its going out of element1 so its moving away from A

    Attached Files:

    • 1.jpg
      File size:
      18.6 KB
  2. jcsd
  3. Jan 17, 2008 #2
    Based on the problems established conventions, it sounds good to me. The current will never actually reach, nor originate, from terminal A because it is an open circuit with infinite resistance.

    Quick edit:
    The one thing I don't like is that current is, by a more universally established convention, the flow of positive charges. This is because the electrons are going to get a force that moves them to the positive terminal of the potential, the battery. I think the problem means what I said, and is just poorly worded.
    Last edited: Jan 17, 2008
  4. Jan 17, 2008 #3

    Shooting Star

    User Avatar
    Homework Helper

    Incorrect. The direction of the flow of the electrons is in the same direction as that of the negative current. Here, the negative 2mA is flowing toward A.

    What is wrong with a current flowing through the closed loop V-1-2?

    (The points A and B here probably represents parts of the circuit not shown, and not just open -ended wires.)
  5. Jan 17, 2008 #4
    Oh, well if A-B is just a load then the current could go to it. The circuits I was taught often had open terminals with infinite impedance to make what voltages the problem was looking for more apparent.

    But yes, I would agree with you that if we are looking at the actual flow of electrons, rather than the flow of positve charges, it would go towards the terminal.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Kirchoff's Law question