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: Time to discharge a capacitor

  1. Jan 26, 2010 #1
    1. The problem statement, all variables and given/known data

    What is the shortest time after which there would be no measurable charge on a 5.0 microfarad capacitor that is charged, then discharged across a 2000 ohm resistance.

    a. 0.001 s
    b. 0.5 s
    c. 10 s
    d. 3600 s

    2. Relevant equations



    3. The attempt at a solution

    According to the time constant the charge on the capacitor should decrease by a factor of 1/e every 0.01 s according to my calculation.

    I don't know how to answer the question though.
     
  2. jcsd
  3. Jan 26, 2010 #2
    How much charge is considered unmeasurable?
     
    Last edited: Jan 26, 2010
  4. Jan 26, 2010 #3
    That's my question. How do I answer this without knowing that?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook