Answer: 63% of the final charge
Explanation:
When a capacitor is connected to a battery/power supply, the capacitor charges following the exponential law:
where
is the final charge of the capacitor, which is
where C is the capacitance and the potential difference of the battery
t is the time
is the time constant of the circuit
Re-writing the equation,
After a time equal to one time constant,
Therefore the charge on the capacitor will be
Which means 63% of the final charge.