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Magnitude of Potential Difference Between Two Points

  1. Mar 10, 2013 #1
    potential diffeence.jpg 1. The problem statement, all variables and given/known data[/b]

    So I found this problem online, and I really do not know how to go about solving it! My professor has done similar problems in class, but it's still a little confusing.

    A current of 1.2 A flows from A to B. Therefore, the magnitude of the potential difference between points A and B is approximately

    2. Relevant equations
    I know Δv=IR and Ampere/Volt makes an Ω

    3. The attempt at a solution

    Well, the image attached already gives the answer, it should be 6.0 V. The current is given (1.2 A), so I'm guessing by the units that I must multiply something with Ω to get Volts. Should I add up the resistors?

    Thank you!
     
    Last edited: Mar 10, 2013
  2. jcsd
  3. Mar 10, 2013 #2

    lewando

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    Gold Member

    To do this problem, you are going to need to be able to "add" resistors in parallel and series. Need help with that?
     
  4. Mar 10, 2013 #3

    gneill

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    Staff: Mentor

    Sure. Find the equivalent resistance between points A and B. Then see what potential drop occurs across it due to the given current value.
     
  5. Mar 10, 2013 #4

    Haha, lewando, yes please!

    Would we consider the two 6Ω resistors parallel? And if so, the potential difference there is the same? We are getting to the point where I just smile and nod during the lecture even though I am completely lost!
     
  6. Mar 10, 2013 #5

    lewando

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    Gold Member

  7. Mar 10, 2013 #6
    Thank you so much! I just had an epiphany and this is all way less complicated! Thank you to all who replied. And thank you so much, lewando. I wasn't taking the reciprocals of the resistances and so I was adding them incorrectly, but now it all makes much more sense. I ended up with an R_eq of 5Ω, which when multiplied by 1.2 A yields a potential difference of 6 V. Thank you so much!
     
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