1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Voltage in a Non-Ideal Battery

  1. Apr 12, 2010 #1
    1. The problem statement, all variables and given/known data
    Given the following circuit:


    What is the actual voltage provided to the circuit by the non-ideal battery if the internal resistance r = 0.50 ohms and the internal emf is 9.0 volts?

    A. 9.8 V
    B. 8.5 V
    C. 9.0 V
    D. 8.4 V
    E. 8.8 V

    2. Relevant equations

    3. The attempt at a solution

    First, do I determine the current in the circuit, I? Then,
    Total resistance in circuit if battery was ideal = 9/I
    9/I - .5= 9/I-.5 ohms. At I amps, the voltage would be (I amps x 9/I-.5) = how ever many V...

    How do I calculate I?
  2. jcsd
  3. Apr 12, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi sweetdion! :wink:

    Find I by first finding the equivalent resistance (including r) …

    then the effective (actual) voltage is the potential difference across that dotted box, which is V minus … ? :smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook