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!

Easy Physics problem I just can't get

  1. Feb 20, 2010 #1
    Easy Physics problem I just can't get :(

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

    In figure 27-62, a voltmeter of resistance RV = 380 Ω and an ammeter of resistance RA = 1.18 Ω are being used to measure resistance R in a circuit that also contains a resistance R0 = 100 Ω and an ideal battery of emf ε = 12.0 V. Resistance R is given by R = V/i, where V is the voltmeter reading and i is the current in the resistance R. However, the ammeter reading is not i but rather i', which is i plus the current through the voltmeter. Thus the ratio of the two meter readings is not R but only an apparent resistance R' = V/i'. If R = 61.2 Ω, what are (a) the ammeter reading in milliamperes, (b) the voltmeter reading (in V), and (c) R'?

    3. The attempt at a solution

    I was able to get part C, 52.71 ohms, which is correct.

    I got 90.36mA for part A, and 4.77 V for part B, but both of those are wrong.

    Please help me get these!
     
  2. jcsd
  3. Feb 20, 2010 #2
    Re: Easy Physics problem I just can't get :(

    drawing the figure given may help...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook