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Using Electric Energy

  1. Dec 4, 2008 #1
    What is the maximum current allowed in a 3.5 W, 220 ohm resistor?

    The answer needs to be in amps so how would I convert watts to volts?
     
  2. jcsd
  3. Dec 4, 2008 #2

    mgb_phys

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    Whats the formula for power dissapation in a resistor?
    hint, V=IR and P=IV
     
  4. Dec 4, 2008 #3
    Because the voltage was unknown you would use both equations and substitution right?
    So P=I(IR) ---> P=I^2R

    So 3.5/220=I^2
    .0159=I^2
    I=.1581

    Is that correct?
     
  5. Dec 4, 2008 #4

    mgb_phys

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    Slight typo/mistake in your sqrt but yes - thats the correct method
     
  6. Dec 4, 2008 #5
    thank you!
     
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