$A$ flat circular disc has a charge $+Q$ uniformly distributed on it. $A$ charge $+q$ is thrown with kinetic energy $E$ towards the disc along its normal axis. The charge $q$ will:

$A$ source of potential difference $V$ is connected to the combination of two identical capacitors as shown in the figure. When key $K$ is closed,the total energy stored across the combination is $E_{1}$. Now key $K$ is opened and a dielectric of dielectric constant $K_{d} = 5$ is introduced between the plates of both capacitors. The total energy stored across the combination is now $E_{2}$. The ratio $E_{1} / E_{2}$ will be:

What are the charges stored in the $1 \,\mu F$ and $2 \,\mu F$ capacitors in the circuit below,once the currents become steady?

Find the potential difference $V_a - V_b$ between the points $a$ and $b$ shown in the figure.

How many $6 \mu F, 200 \ V$ capacitors are needed to make a capacitor of $18 \mu F, 600 \ V$?

The two plates $X$ and $Y$ of a parallel plate capacitor of capacitance $C$ are given a charge of amount $Q$ each. $X$ is now joined to the positive terminal and $Y$ to the negative terminal of a cell of $emf$ $E = Q/C$.