Recently I have learned about the behaviours of capacitors are as follows:
When connected to a voltage source the voltage on the the plate on the positive side begins to rise slowly until it reaches the same voltage as the supply, while the other plate, which is connected to ground, remains at 0v.
Capacitors have the tendency to keep the voltage across two plates the same, and therefore if one is 10v and the other is 0v, and the 10v is suddenly pulled to ground, the other plate will be pulled to -10v to maintain the voltage differences.
These two statements seem contradicting to me. Specifically, if capacitors tends to keep plates voltage the same, then why when it charges, the other plate remains 0v? And unlike voltage rising(charging) which happens gradually over time, why does the plate voltage change from 10v and 0v to 0v and -10v instantaneously when pulled directly to ground, that is, why in this case it doesn’t lower its voltage gradually over time?