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Question
Three circuits, each consisting of a switch 'S' and two capacitors, are initially charged, as shown in the figure. After the switch has been closed, in which circuit will the charge on the left-hand capacitor
(i) increase,
(ii) decrease, and
(iii) remains the same? Give reasons.
Solution
When charged capacitors are connected to each other then the charge will flow from the capacitor with higher potential towards the capacitor with lower potential until a common potential is reached.
(a) In fig. (a) the potential of both the capacitor is same so the charge on left hand capacitor remains the same.
(b) In fig. (b) the potential of left hand capacitor is high so charge from 6Q to 3Q. Therefore charge on left hand capacitor will decrease. (c) In fig.
(c) the potential of left hand capacitor is low so charge will flow from 3Q to 6Q. Therefore charge on the left-hand capacitor will increase.
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