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Finding electrical energy used by a light

  1. Mar 6, 2014 #1
    1. The problem statement, all variables and given/known data

    find electrical energy used by the light if the voltage on the battery is 110 V and the current in 2.0 minutes is 10 mA

    V = 110
    I = 10 mA


    2. Relevant equations

    R = V/I


    3. The attempt at a solution

    110 V /.010 A

    = 11,000 ohms

    = 11 k ohms


    I'm new to this, did I do this problem right?
     
  2. jcsd
  3. Mar 6, 2014 #2

    CWatters

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    The SI unit of energy is the Joule. The Ohm is the unit of resistance.
     
  4. Mar 6, 2014 #3
    Which is the correct formula that I should be using?
     
  5. Mar 6, 2014 #4

    PhysicoRaj

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    Think of a formula that links all the givens, that is, voltage, current, time and energy.
     
  6. Mar 6, 2014 #5

    CWatters

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    Might be easier to find two formula?

    One that gives you the power from some of the givens.
    One that gives you energy from power and another given.
     
  7. Mar 7, 2014 #6
    I think I found it

    P = I * V

    then I multiply power, in watts, by 2 minutes and I got an answer in Joules, is that it?
     
  8. Mar 7, 2014 #7

    PhysicoRaj

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    Note the SI unit for time..
     
  9. Mar 7, 2014 #8
    multiply by 120 seconds
     
  10. Mar 7, 2014 #9

    PhysicoRaj

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    Job done :thumbs:
     
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