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!

Another one of them circuit questions

  1. Mar 22, 2005 #1
    The circuit in the drawing shows two resistors, a capacitor and a battery. When the capacitor is fully charged, what is the magnitude of q of the charge on one of its plates?

    Here's what I got so far:

    So 12= 2I + 4I

    Since q=CV and I have C=9.0uF, all I need is the voltage. And since the voltage drop between parallel circuits is the same then all I have to find is the voltage at the node going into 4 ohm resistor? Sounds like a good method but I can't seem to get the voltage drop.

    Any ideas? :uhh:
     

    Attached Files:

  2. jcsd
  3. Mar 22, 2005 #2
    okay for those who can't see the attachment because it's waiting approval:

    Code (Text):


    |-R=2.0ohm-|--------|
    |                |           |
    V=12V        R=4ohm  C=9.0uF
    |                |           |
    |__________|_______|          

     
    Ok where I placed the letters is where you'll get a resistor or capacitor or voltage etc.
    ugh, the code thing doesn't work so well, but the R=4ohm is in the middle branch and the C=9.0uF is at the end branch.
     
  4. Mar 22, 2005 #3
    Ack, I got it nvm.

    Easy really, almost had it too

    12=2I+4I, I=2

    V=IR at the 4
    V=2*4
    V=8 Volts

    q=CV
    =9.0x10^-6Fx8Volts
    =7.2x10^-5 C.

    Thanks notaphysicsman :)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?