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

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 $V$)

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

For the circuit shown in the figure,the charge on the $4 \mu F$ capacitor is $....... \mu C$.

An $\alpha$ particle and a proton are accelerated from rest through the same potential difference. The ratio of linear momenta acquired by the above two particles will be:

In the figure,the area of each plate is $A$ and the distance between consecutive plates is $d$. What is the effective capacitance between points $A$ and $B$?