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What is the current in this circuits?

  1. Oct 29, 2016 #1
    1. The problem statement, all variables and given/known data
    whe22q.jpg


    2. Relevant equations
    Ohm's Law : V = IR, Eel = VIt , Vt=ItRt , Q=It

    3. The attempt at a solution

    I tried to do the first question letter a

    I=? I= V/R
    R=3 ohms I= 6/3
    V=6V I=2A


    i dont know how to continue the others :/
     
  2. jcsd
  3. Oct 29, 2016 #2

    Merlin3189

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    Gold Member

    So far, so good, so long as you know what it is that you have worked out.

    Your final line says, V=6V I=2A so now you know V,I and R for the 6Ω resistor

    So now, what do you know about the 3Ω resistor?
     
  4. Oct 29, 2016 #3
    I dont know if I can work out b) without any given volts in the 2nd 1ohm resistor
     
  5. Oct 29, 2016 #4

    gneill

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    What type of circuit is depicted? Is it series-connected or parallel-connected?
     
  6. Oct 29, 2016 #5

    Merlin3189

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    But you haven't said what you DO know about it!
    I'll give you a start. You know R is 1Ω. Now, can you tell me what I or V is? (without doing any calculation yet.)

    If you say you know neither I nor V, you could try drawing on the circuit, or think about gneill's question,. .Because you DO know one of them! And you only need 2 out of 3 to work out the other.
     
  7. Oct 30, 2016 #6
    its connected in series meaning voltage is divided among components.

    V - volts , I - current.

    I dont know the volts of the battery
     
  8. Oct 30, 2016 #7

    cnh1995

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    You need not know that.
    What else does that mean? What about the current through the series components?
     
  9. Oct 30, 2016 #8

    series same current
     
  10. Oct 30, 2016 #9

    gneill

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    So then, what is the current through the 1 Ω resistor?
     
  11. Oct 30, 2016 #10
    2A?
     
  12. Oct 30, 2016 #11

    gneill

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    Yes. It's a series circuit so there is only one current.
     
  13. Oct 30, 2016 #12
    thanks
     
  14. Oct 30, 2016 #13

    cnh1995

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    Yes. So what is the voltage across the 1 ohm resistor?
     
  15. Oct 30, 2016 #14
    for b) 2A

    c) v=Ir
    2x1=2volts
     
  16. Oct 30, 2016 #15

    cnh1995

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    Yes. Now you have sufficient information to calculate the p.d. across the battery.
     
  17. Oct 31, 2016 #16
    for d) is it 6V + 2V = 8V?

    e) each cell has 2v?
     
  18. Oct 31, 2016 #17

    cnh1995

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    Yes.
     
  19. Oct 31, 2016 #18
    Thanks thats a question done.

    For the next problem,

    a) 1.5x4 = 6V
    b)
    V?
    R=6ohm
    I= 1? (v/ohm,6/6)

    6x1=6V?

    c) 1A?

    thanks alot man
     
  20. Oct 31, 2016 #19

    cnh1995

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    Yes.
     
  21. Oct 31, 2016 #20
    d)

    v=?
    r=3ohm
    i=2a(6/3)

    v=ir 2x3 = 6V?

    e)2A?

    but how come can both be 6V when its a 6V battery?
     
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