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Homework Help: Energy transferred in radio

  1. Dec 13, 2015 #1
    1. The problem statement, all variables and given/known data
    How much energy is transferred to a radio if a current of 0.40A run through it for 1.5 minutes with 115V?

    t=1.5 min

    2. Relevant equations
    Not sure which equation to use.

    3. The attempt at a solution
    Not sure which equation to use.
  2. jcsd
  3. Dec 13, 2015 #2
    Use the GUESS method: Given, Unknown, try to find an Equation that kind of fits the given and unknown quantities (or just multiply every given number), Substitute the numerical values, "Solve".

    (None of this requires any insight in the physics, of course. It is just a way of getting through schools with this kind of teaching.)
  4. Dec 13, 2015 #3
    I could use Q=Ixt right?
  5. Dec 13, 2015 #4


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    Is Q energy, or something else?

    What's the definition of electric current?
  6. Dec 13, 2015 #5
    Yes, the charge Q is proportional to current and duration, but there is no build-up of charge in a radio, it is not very relevant in this context.
  7. Dec 13, 2015 #6
    Okay first I would use Q=Ixt and then I would use E=VQ.
  8. Dec 13, 2015 #7
    And that would be the right answer!
    (But it also reveals a complete lack of understanding... I am not blaming you, it is the way you are being taught.)
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