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Question
Three capacitors each of capacitance 9 pF are connected in series.
- What is the total capacitance of the combination?
- What is the potential difference across each capacitor if the combination is connected to a 120 V supply?
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Solution
Capacitance of each of the three capacitors,
C1 = C2 = C3 = 9 pF
V = 120 volt
(a) Total capacitance of the combination,
For capacitors in series:
`1/C_(eq) = 1/C + 1/C + 1/C`
`1/C_(eq) = 1/9 + 1/9 + 1/9`
= `1/3`
Ceq = 3 pF
Hence, the total capacitance of the combination is 3 pF.
(b) Potential difference (V') across each capacitor is equal to one-third of the supply voltage.
∴ `V' = V/3`
= `120/3`
= 40 V
Therefore, the potential difference across each capacitor is 40 V.
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