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Homework Help: Current electricity

  1. May 26, 2010 #1
    when the terminals of a single cell are connected by means of a conducting wire with no resistor component is there a current flow through the wire ?

    jus started with current electricity have a lot of doubts thanx for any help
     
  2. jcsd
  3. May 26, 2010 #2

    ehild

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    Yes, a very big current will flow, limited only by the own resistance of the cell. If you do it with a simple battery, you even get a spark, and the battery gets flat very soon. But it is worth trying and see with your own eyes if there is current or not :)

    ehild
     
  4. May 26, 2010 #3
    u mean to say if we keep such a system undisturbed 4 a long time the battery will get exhasted soon?
     
  5. May 26, 2010 #4
    is the current through this loop
    I=(E1+E2)/(r1+r2)
    n terminal p.d across cell 1 &2

    E1-Ir1 & E2-Ir2 respectively
     

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    Last edited: May 26, 2010
  6. May 26, 2010 #5

    ehild

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    You can not keep it undisturbed for a long time, as either the battery gets exhausted and no more current will flow, or it starts to burn and smell and everything. Why don't you try? It is better to see things than constructing theories about them, and this experiment is not very dangerous, unless you hold the wire with bare hand... If you do, your fingers will burn. But you get experiences about the nature of battery, current and its heating effect so it is worth trying... Well, a good boy or girl never does such things, but a future physicist does. :)

    (To tell the truth I started my lectures on practical electricity by giving my pupils a little electric shock)

    ehild
     
  7. May 26, 2010 #6
    thanku so much y is d spark produced?
     
  8. May 26, 2010 #7
    what is the terminal pd across the cell in that case?
     
  9. May 26, 2010 #8

    ehild

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    It is practically zero if the resistance of that short piece of wire is much less than the internal resistance of the battery (this internal resistance is about 1 ohm in case a common 4.5 V battery) The potential will drop across the internal resistance, inside the battery.

    ehild
     
  10. May 26, 2010 #9
    thanku so much
     
  11. May 26, 2010 #10
    hey can someone plz help me with the other question too?
     
  12. May 26, 2010 #11
    How to find i1 and i2?
     

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  13. May 27, 2010 #12

    ehild

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    Write the problem in words. I do not understand your drawing.


    ehild
     
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