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!

What is the value of the loss volt and internal resistance of the battery?

  1. May 9, 2008 #1
    1. The problem statement, all variables and given/known data
    When a current of [tex]2A[/tex] flows the p.d across a battery's terminal falls from [tex]12V[/tex] to [tex]9V[/tex].
    (a) What is the value of the loss volt?
    (b) What is the internal resistance of the battery?

    2. Relevant equations
    Lost Volt = Ir

    3. The attempt at a solution
    (a) [tex]12V - 9V = 3V[/tex]

    [tex]R = \frac{V}{I} = \frac{3}{2} = 1.5[/tex]

    [tex]Lost Volt = 3 \times 1.5 = 4.5[/tex]

    Is this correct?

    (b) Don't know which equation to use :confused:
     
  2. jcsd
  3. May 10, 2008 #2
    your last 4.5 is wrong and no need. It is (lost volt)*(internal rezistance of battery) and meaningless.

    Lost volt: 3V
    R=1.5 ohm
     
  4. May 10, 2008 #3

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper


    You can always check by using units in the calculation:
    [tex]3V \times 1.5 \mbox{ohms} = 4.5 \ V\times \mbox{ohms} [/tex]

    Since the units (V x ohms) are not Volts, this can't be right.

    R = V/I, you already did it without realizing it :smile:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: What is the value of the loss volt and internal resistance of the battery?
Loading...