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: Capacitance equired to store an energy of

  1. Oct 9, 2005 #1
    Hello everyone. The question is:
    What capacitance is required to store an energy of 8 kWh at a potential difference of 600 V?
    \This seems like a simple problem..our professor hasn't went over this yet but i saw in the book. P = U/t; I also saw; U = 1/2CV^2; So they gave me U right? because P = U/t, so U = 8 kWh, i converted this into 8kWsecond, by doing this:
    8kwh x 3600sec = 28800kws; I then used:
    C = (2U)/v^2; C = [2*28800]/(600)^2 = .16 which was wrong, i also tried just using 8, and 8/3600, all didn't work.
  2. jcsd
  3. Oct 10, 2005 #2


    User Avatar
    Homework Helper

    1 KWH = 1*1000*3600 J = 3.6 x 10^6 J (S.I. Unit of energy)
  4. Oct 10, 2005 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There is still the KILO in there, which you should convert numerically (hint: 1000:-)
  5. Oct 11, 2005 #4
    Ahhh thank you guys, worked great :)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook