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Homework Help: How many joules of energy are supplied.

  1. Sep 28, 2011 #1
    1. The problem statement, all variables and given/known data
    How many coulombs of electricity pass through a lamp when a current of 5A flows for 3 minutes. Answer: 900C
    In this time 27,000 joules of electrical energy is converted into heat and light. How many joules of energy are supplied by each coulomb.

    2. Relevant equations
    V=W/q
    E=Pt
    P=VI

    3. The attempt at a solution
    27000/900 = 30V
    P=30 x 5 = 150W
    E= 150 x 180 = 2700

    Have I done this correctly?
     
  2. jcsd
  3. Sep 28, 2011 #2
    Your first part is correct, not sure what you're trying to do with all those other equations listed though to calculate how much energy is supplied by each coulomb. It's a lot easier than what you're trying to do.
     
  4. Sep 28, 2011 #3

    NascentOxygen

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    Staff: Mentor

    one volt is one Joule/coulomb
     
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