$125$ identical drops,each charged to a potential of $50\;V$,are combined to form a single drop. The potential of the new drop will be......$V$.

$A$ soap bubble is given a negative charge,then its radius

$A$ $4\,\mu F$ capacitor is connected in parallel to another capacitor of $8\,\mu F$. Both the capacitors are then connected in series with a $12\,\mu F$ capacitor and charged to $20\;V$. The charge on the plate of the $4\,\mu F$ capacitor is......$\mu C$.

What is the effective capacitance between points $X$ and $Y$ in the given circuit? (All capacitors are in $\mu F$)

$A$ parallel plate capacitor of plate area $A$ and plate separation $d$ is charged to a potential $V$ and then the battery is disconnected. $A$ slab of dielectric constant $k$ is then inserted between the plates of the capacitor so as to fill the space between the plates. If $Q$,$E$,and $W$ denote respectively the magnitude of charge on each plate,the electric field between the plates (after the slab is inserted),and the work done on the system in the process of inserting the slab,then state the incorrect relation from the following:

Two capacitors of $2 \mu F$ and $3 \mu F$ are charged to $150 \ V$ and $120 \ V$ respectively. The plates of the capacitors are connected as shown in the figure. $A$ discharged capacitor of capacity $1.5 \mu F$ is connected to the free ends of the wire. Then: