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Homework Help: Ohms law

  1. May 24, 2008 #1
    1. The problem statement, all variables and given/known data
    You would like to check if the battery voltage drops while it is supplying a current of 6A. You use a voltmeter designed to measure voltages up to 20V and having a resistance of 50,000 Ohms.
    See attachment****

    This connection is in series so V= I (R1+R2)
    V / (R1+R2) = I
    12 / (2+ 50000) = I
    2.39E-4 = I

    How much current (in A) would flow through the headlight for Circuit b?

    The connection is in parallel so Req = (1/ R1 + 1/R2)
    Req = (1/2 + 1/50000) = .50002

    I = V / R
    I = 12 / .50002
    I= 23.99

    2. Relevant equations
    I want to check if what I have done is right.

    3. The attempt at a solution
    Is right bellow the questions.


    Attached Files:

    • phy.jpg
      File size:
      25 KB
  2. jcsd
  3. May 24, 2008 #2
    You have your formula for Req wrong.

    It should be 1/Req= (1/R1 + 1/R2)

    So, Req = 1.99992.
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