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Homework Help: What does the Voltmeter read?

  1. Jun 4, 2017 #1


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

    2. Relevant equations
    Ohm's Law (V=IR)

    3. The attempt at a solution
    These are my two attempts at getting to the solution. I'm really finding it difficult to tackle this question (our teacher gave it as an optional challenge). The provided answer on the worksheet is ɛ/2, but I have no clue how to get there. Any help is much appreciated.

    Attached Files:

  2. jcsd
  3. Jun 4, 2017 #2
    An ideal voltmeter is one that has infinite resistance. Use KVL, the resistor to the rightmost (nearest to terminal A) is short circuited anyway, so you are left with two resistors of equal resistance.

    All measuring devices conncected to a circuit adveresly effect it, ideal ones dont. Since a voltage measurement is always made parallel to elements there must not be any current flowing into the voltmeter I believe, and this is achieved by having an infinite resistance. :-)
  4. Jun 4, 2017 #3


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    Staff: Mentor

    Hi Gex,

    Unfortunately your images are essentially unreadable. Please make a new thread and type out your work or provide better pictures (preferably the former). I highly recommend learning a little bit of LaTeX. It greatly helps with inserting math into your posts. We have a primer for it here: https://www.physicsforums.com/help/latexhelp/

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