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Homework Help: Need help with two questions, dealing with electricity

  1. Feb 19, 2010 #1
    Hi, i have two questions from my assignment that i am having a very hard time understanding....

    1. A piece of Nichrome wire has a radius of 6.5x10^-4 m. It is used in a laboratory to make a heater that uses 4.00x10^2 W of power when connected to a voltage source of 120 V. Ignoring the effect of temperature on resistance, estimate the necessary length of wire.


    2.A light bulb is connected to a 120.0 V wall socket. the current in the bulb depends on the time (t) according to the relation I = (0.707 A)sin[(314Hz)t]. (a) what is the frequency of the alternating current? (b) determine the resistance of the bulb's filament. (c) what is the aaverage power deliever to the light bulb?


    Could someone please help me out
     
  2. jcsd
  3. Feb 19, 2010 #2

    rock.freak667

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    Homework Helper

    P=V2/R will help you.

    I=I0sin(ωt)
     
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