The switch $S$ shown in the figure is kept closed for a long time and then opened at $t = 0$. The current in the middle $20\, \Omega$ resistor at $t = 0.25\, ms$ is:

In the given figure,initially the capacitor is uncharged. The ratio of current at $t = 0$ and $t = \infty$ will be:

$A$ capacitor of capacity $C$ is charged to a steady potential difference $V$ and connected in series with an open key and a pure resistor $R$. At time $t = 0$,the key is closed. If $I$ is the current at time $t$,a plot of $\log I$ against $t$ is as shown in $(1)$ in the graph. Later,one of the parameters,i.e.,$V, R,$ or $C$,is changed while keeping the other two constant,and the graph $(2)$ is recorded. Then:

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 .........

After the switch shown in Figure $A$ is closed,there is a current $i$ through the resistance $R$. Figure $B$ indicates current variation curves $a, b, c,$ and $d$ for four sets of values of $R$ and capacitance $C$:
$(i)$ $R_0$ and $C_0$
$(ii)$ $2R_0$ and $C_0$
$(iii)$ $R_0$ and $2C_0$
$(iv)$ $2R_0$ and $2C_0$
Which set goes with which curve?

As shown in the figure,if a capacitor $C$ is charged by connecting it with a battery of voltage $V$ through a resistance $R$,then the energy supplied by the battery will be: