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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, C = 9 pF
Equivalent capacitance (C') of the combination of the capacitors is given by the relation,
`1/"C'" = 1/"C" + 1/"C" + 1/"C"`
`1/"C'" = 1/9 + 1/9 + 1/9`
= `1/3`
C' = 3 pF
Therefore, the total capacitance of the combination is 3 pF. - Supply voltage, V = 120 V
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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