The charge across the capacitor in two different $RC$ circuits $1$ and $2$ are plotted as shown in the figure. Identify the correct statement$(s)$ related to the $R_1, R_2, C_1$ and $C_2$ of the two $RC$ circuits.

$A$ combination of two identical capacitors, a resistor $R$, and a $DC$ voltage source of voltage $6\; V$ is used in an experiment on a $C-R$ circuit. It is found that for a parallel combination of the capacitors, the time in which the voltage of the fully charged combination reduces to half its original voltage is $10\; s$. For a series combination, the time needed for reducing the voltage of the fully charged series combination by half is: (in $; s$)

In the circuit shown in the figure,$C_1 = 2C_2$. Switch $S$ is closed at time $t = 0$. Let $i_1$ and $i_2$ be the currents flowing through the branches containing $C_1$ and $C_2$ respectively at any time $t$. Then the ratio $i_1 / i_2$:

$A$ capacitor of capacitance $C = 1 \, \mu F$ is suddenly connected to a battery of $100 \, V$ through a resistance $R = 100 \, \Omega$. The time taken for the capacitor to be charged to $50 \, V$ is $.... \times 10^{-4} \, s$. (Take $\ln 2 = 0.69$)

$A$ capacitor is connected to a $20\, V$ battery through a resistance of $10\, \Omega$. It is found that the potential difference across the capacitor rises to $2\, V$ in $1\, \mu s$. The capacitance of the capacitor is $....\, \mu F$. Given: $\ln(10/9) = 0.105$.

What are the charges stored in the $1 \mu F$ and $2 \mu F$ capacitors in the circuit as shown in the figure once the current $(I)$ becomes steady?