As shown in the figure,the work done in moving a charge $q$ from $A$ to $B$ and from $B$ to $C$ is $2 \ J$ and $-3 \ J$ respectively. The work done in moving the charge from $C$ to $A$ will be ...... $J$.

The following figure shows a $9 \ V$ battery and $3$ uncharged capacitors of capacitances $C_1 = C_2 = C_3 = 1 \ \mu F$. The switch is thrown to the right side until capacitor $C_1$ is fully charged,then the switch is thrown to the left. The final charge on capacitor $C_2$ is (in $\mu C$)

Find the potential difference between points $A$ and $F$,and $F$ and $B$.

Assuming the drops to be spherical,$27$ identical drops of mercury are charged simultaneously to the same potential of $20 \ V$. If all the charged drops are made to combine to form one big drop,then the potential of the big drop will be: (in $V$)

In the circuit shown in the figure,$K$ is open. The charge on capacitor $C$ in the steady state is $q_1$. Now,the key $K$ is closed,and at the steady state,the charge on $C$ is $q_2$. The ratio of charges $\left( \frac{q_1}{q_2} \right)$ is:

Three point charges $1 \ C$,$-2 \ C$,and $-2 \ C$ are placed at the vertices of an equilateral triangle of side $1 \ m$. The work done by an external force to increase the separation of the charges to $2 \ m$ in joules is ($\varepsilon_0 =$ permittivity of air).