What is the charge on the capacitor being charged up by a 25 V battery

[ahazen]

A capacitor in a RC circuit is initially uncharged. What is the charge on the capacitor being charged up by a 25 V battery for a period of two time constants of the RC circuit? (C = 15 µF, R = unknown)


How do I find Q?

 

[fss]

Sounds like you need to get a better understanding of how the time constant is defined.