a 2mF capacitor is intially charged by a 24v battery, this battery is later disconnected and the capacitor is then connected to another 1mF capacitor. What is conserved in the system (explain), What is the total charge of the system?

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radar · Answer

|dw:1453771772394:dw||dw:1453771948146:dw|After the 2 mF capacitors has been charged, it will have a voltage of 24 volts, disconnecting the battery, there will still be 24 volts across the capacitor.
But when the 1 mF capacitor is connected the voltage will have to be distributed across the two capacitors which are now in series as there is only one path for current which only occurs when the connection is initially made.  
First calculate the charge before the connection is made. C=2 mF (millifarad), V=24 Volts.  The charge Q will be equal to CV or 2 10^-3 (24) or 48 milli coulombs.