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Capacitors question

  1. Jun 6, 2015 #1
    1. The problem statement, all variables and given/known data
    A capacitor has a capacitance of 5μF. If its fully charged from a 12V battery;
    i) What will its charge on its plates at the end of the process
    ii) The combined capacitance if the capacitor is connected in parallel with another 10μF capacitor
    iii) The combined capacitance if the capacitor is connected in series with another 10μF capacitor

    2. Relevant equations
    i) C=Q/V
    ii) Ctotal=C1+C2
    iii) ii) 1/Ctotal=1/C1+1/C2

    3. The attempt at a solution
    i) Q=CV .:. Q=60A
    ii) 15μF
    iii) 1/Ctotal = 3/10 .:. Ctotal=10/3
     
  2. jcsd
  3. Jun 6, 2015 #2

    SammyS

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    Your answer (i) for charge has the wrong units.

    Your answer to (ii) is correct.

    Your answer to (iii) has no units.
     
  4. Jun 6, 2015 #3
    Sorry, I meant C(Coulombs)
    and is part iii) correct if I'd added uF ?
     
  5. Jun 6, 2015 #4

    SammyS

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    Yes. (10/3)μF is correct.
     
  6. Jun 8, 2015 #5

    rude man

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    part (i) is still wrong, even after changing A to C.
     
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