$A$ capacitor is connected to a cell of $emf$ $E$ having some internal resistance $r$. The potential difference across the

$A$ capacitor is charged to a potential difference of $100\, V$ and then connected across a resistor. The potential difference across the capacitor decays exponentially with time. After $1\, s$,the potential difference across the capacitor plates is $80\, V$. What is the fractional loss of the stored energy?

Find the charge on the capacitor $C$ in the following circuit in $\mu C$.

The plates of a capacitor are charged to a potential difference of $V \, \text{volts}$ and then connected across a resistor. The potential difference across the capacitor decreases exponentially with respect to time. After one second, the potential difference between the plates is $V/3$; then after two seconds from the start, the potential difference between the plates is

The circuit shown in the figure consists of a charged capacitor of capacity $3\, \mu F$ and a charge of $30\, \mu C$. At time $t = 0,$ when the key is closed,the value of current flowing through the $5\, M\Omega$ resistor is $'x'\, \mu A$. The value of $'x'$ to the nearest integer is .........

The time in seconds required to produce a potential difference of $20 \ V$ across a capacitor of $1000 \ \mu F$ when it is charged at a steady rate of $200 \ \mu C/s$ is