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: Rate of Thermal Energy

  1. Mar 26, 2007 #1
    An inductor used in a DC power supply has an inductance of 13H and a resistance of 160 ohms. It carries a current of 0.4 A. What is the stored energy in the magnetic field? At what rate is thermal energy developed in the inductor?

    L=13H
    R=160 ohms
    I=0.4A

    W = 1/2Li^2 = 1/2(13)(0.4)^2 = 1.04 J

    I am unsure where to go from here. I can calculate the stored energy, but what do I do for the rate of thermal energy?
     
  2. jcsd
  3. Mar 26, 2007 #2

    berkeman

    User Avatar

    Staff: Mentor

    Your answer for the stored magnetic energy looks correct. Now, the thermal energy dissipated actually has very little to do with the stored magnetic energy in this DC question. Think of the thermal losses as "Ohmic losses". Does that hint help?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook