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Homework Help: In a series circuit with 3 bulbs, does the voltage decrease?

  1. Nov 10, 2012 #1
    In a series circuit with 3 bulbs, does the voltage across each bulb decrease? I know the current is the same at all points in the circuit. My book says that the brightness of the bulbs are all equal. Is this true?

    My idea is that the brightness will not be the same because of the resistance of each bulb. I'm not sure if I am correct.

    Thanks in advance.
  2. jcsd
  3. Nov 10, 2012 #2

    Andrew Mason

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    If the bulbs are identical, they will all have the same brightness.

    The brightness is determined by the power consumed by the bulb. The power consumed by each bulb is EI where E is the voltage measured across the terminals of each bulb and I is the current (I being the same for each bulb). Since E = IR and they all have the same resistance, EI is the same for each bulb.

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