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Homework Help: How much of this energy is stored in the magnetic field of the inductor?

  1. Dec 8, 2005 #1
    For the circuit of Figure 30-19, assume that EMF= 14.0 V, R = 5.40 , and L = 5.00 H. The battery is connected at time t = 0.
    Picture:
    http://www.webassign.net/hrw/hrw7_30-19.gif
    Okay i know there is a simple formula to find the:
    (a) How much energy is delivered by the battery during the first 2.00 s?
    J

    but i don't know where it is, anyone know it?

    Also I tried part (b) and got it wrong for some reason:
    How much of this energy is stored in the magnetic field of the inductor?
    wrong check mark J

    I used:
    V = iR.
    Ub = .5L*i^2;
    i = 14/5.40 = 2.59 Amps
    Ub = .5*5.00*2.59^2 = 16.77 but they didn't like that at all, any ideas?
    thanks.
     
  2. jcsd
  3. Dec 8, 2005 #2

    ranger

    User Avatar
    Gold Member

    When you analyze a L/R circuit, follow these simple rules:


    You can refer to here for more info.
    http://www.ibiblio.org/obp/electricCircuits/DC/DC_16.html [Broken]
     
    Last edited by a moderator: May 2, 2017
  4. Dec 9, 2005 #3
    Ahhh thanks for the help, i'm all done now with electricity and magnetsim, w00t! I got an A in the class, thanks everyone! :biggrin:
     
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