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Homework Help: What is the voltage across battery terminals?

  1. Mar 14, 2016 #1
    1. The problem statement, all variables and given/known data

    Three resistors are connected to a real battery. The open circuit voltage of the battery is 4.5 Volts. The voltage across the 5 Ohm resistor is 2.5 Volts.

    A) What is the voltage across battery terminals?
    B) What is the internal resistance of the battery?

    Here's a picture of the circuit: http://imgur.com/7IdSn3I

    2. Relevant equations

    Junction Law: Sum of Current in = Sum of Current out

    3. The attempt at a solution

    I understand how a real battery has an internal voltage and resistance, but I don't know how the information here relates to that. I tried using the Junction Law to find different Currents I_1 and I_2 but even after getting those I didn't know how to relate that to the questions.
  2. jcsd
  3. Mar 14, 2016 #2


    User Avatar

    Staff: Mentor

    Can you show what calculations you've done and which currents you've found (they were not marked on your figure)?
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