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Homework Help: Electric field of lightbulb

  1. Feb 27, 2006 #1
    what is the electric field 1m away from a 100 watt light bulb

    i know that the power of the light bulb 100 watt = volts x amps

    so if the light bulb is a standard 120 volts then the electric field would be V / r

    im not sure about this because i know the electric field radiating from the light bulb is a wave
  2. jcsd
  3. Feb 27, 2006 #2


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    Staff: Mentor

    The main element in the lightbulb is the filament, with one end being driven with the 120Vrms voltage waveform, and the other end held at neutral (the metal threads end). Since the metal threads are basically at earth ground potential (actually neutral, but that's close), the majority of the capacitance from the center conductor and the 120Vrms end of the filament will be to the metal threads. What does that tell you about the electric field lines?
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