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!

(E&M) Don't understand why terminals of battery are switched

Tags:
  1. Jul 28, 2014 #1
    In the Princeton Review Cracking the AP Physics C Exam 2011 Edition book on example 11.9's solution, one of the batteries' terminals are swapped (the battery with 10V). I am not sure why the author's do this considering the current is drawn the same. Later on in the solution, they recognize that the terminals are switched when they state that the potential drops as a result of going from positive to negative (even though originally it was negative to positive).

    PROBLEM:
    Use Kirchhoff's Rules to determine the current through R2 in the following circuit:
    l2eZ37Vl.jpg

    WHERE I'M LOST:
    I circled the parts of the illustration where the battery terminals are switched.
    0a5xpaBl.jpg

    During the explanation of the solution, it states that "From e to f, we travel through E2 from the positive to the negative terminal, so the potential drops by E2." so their intentions were to switch the terminals but I'm not sure why we are allowed to do that.

    Here is a full page scan of most of the solution(the little bit that is not included here is not necessarily essential in this case)
    Dv8JrZjl.jpg
     
    Last edited: Jul 28, 2014
  2. jcsd
  3. Jul 28, 2014 #2

    vela

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    You're not allowed to do that. The original circuit diagram probably just has a 'typo.'
     
  4. Jul 28, 2014 #3
    Ok, I see now. Thanks for the clarification.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: (E&M) Don't understand why terminals of battery are switched
Loading...