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DC circuits

  1. Mar 24, 2004 #1
    Hi all,

    I really need somebody to explain to me how to work the following problem...

    A 1.50E2 - W heater is designed to operate with an EMF of 120V. If the potential difference across the heater changes by a small amount such as 2.6%, approximately by what factor does the power change? (Hint: approximately the changes with differentials) (unit %).

    can somebody kindly explain to to go about it?? thanks
  2. jcsd
  3. Mar 24, 2004 #2


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    Science Advisor

    Ok, how about trying this.


    E is voltage or potential
    I is current
    R is resistance
    P is power

    The resistance should be fixed. Solve the latter eq to establish the relationship between E and P.

  4. Mar 24, 2004 #3

    Doc Al

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    Staff: Mentor

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