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Parallel Resistor

  1. Oct 27, 2007 #1
    The figure shows six identical bulbs connected to an ideal battery. All the bulbs are glowing
    Please see attached file.
    Rank in order, from brightest to dimmest, the brightness of bulbs A to F.
    Thank you

    copy from Physics for Scientists and Engineering with Modern Physics by Randall D. Knight.

    Attached Files:

  2. jcsd
  3. Oct 27, 2007 #2
    show ur attempt.
    or, are you trying to check us??
  4. Oct 28, 2007 #3
    OK - you get a little hint:
    You need to figure the currents in each bulb, not in amps, but in terms of bulb resistances.
    The current in D is going to be affected by everything that goes on with B, C, E, F.
    Before you can get that right, realize you need to figure what C and E look like taken together.

    You have a formula for resistors in series and in parallel. Figure out some alternative diagrams with new resistances representing the combinations of bulbs. Look at the branches, and figure that a current arriving has to split, being shared between the resistances with the most share going to the arms with the lower resistances in inverse proportion

    Start off by thinking about bulb A compared to bulb D. Come back with what you have.
  5. Oct 28, 2007 #4
    Just a side note: light bulbs have negative resistance and hysteresis. If your teacher did not specify, my guess would be that you are to assume the bulbs act just like resistors.

    We do need some evidence that you have tried to solve the problem, or at least some questions from you that indicate you are thinking about it, before we can help much more than by giving you the theory.
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