At time $t=0$,a battery of $10 \ V$ is connected across points $A$ and $B$ in the given circuit. If the capacitors have no charge initially,at what time (in seconds) does the voltage across them become $4 \ V$? [Take $\ln 5=1.6, \ln 3=1.1$]

$A$ $2500 \,\mu F$ capacitor is charged through a $1 \,k\Omega$ resistor by a $12 \,V$ d.c. source. The voltage across the capacitor after $5 \,s$ is ..... $V$.

When the key $K$ is pressed at time $t = 0$, which of the following statements about the current $I$ in the resistor $AB$ of the given circuit is true?

$A$ capacitor is discharging through a resistor $R$. Consider in time $t_{1}$,the energy stored in the capacitor reduces to half of its initial value and in time $t_{2}$,the charge stored reduces to one-eighth of its initial value. The ratio $t_{1} / t_{2}$ will be ................

$A$ $20 \mu F$ capacitor is connected to a $45 \text{ V}$ battery through a circuit whose resistance is $2000 \Omega$. What is the final charge on the capacitor?

The charge on a capacitor of capacitance $10\,\mu F$ connected as shown in the figure is.......$\mu C$