Three capacitors of capacitances 1$\mathrm{\mu }$F, 2$\mathrm{\mu }$F and 3$\mathrm{\mu }$F are connected series.
(a) What is the ratio of charges ?
(b) What is the ratio of potential differences ?

In series combination charge remains constant
(a) ratio of charges
$={\mathrm{Q}}_1:{\mathrm{Q}}_2:{\mathrm{Q}}_3=1:1:1$
(b) $\mathrm{Q}=\mathrm{CV}\text{ or }C \alpha \frac{1}{\mathrm{V}}$
ratio of potential differences.
$\begin{array}{l}{\mathrm{V}}_1:{\mathrm{V}}_2:{\mathrm{V}}_3=\frac{1}{{\mathrm{C}}_1}:\frac{1}{{\mathrm{C}}_2}:\frac{1}{{\mathrm{C}}_3}\\ {\mathrm{V}}_1:{\mathrm{V}}_2:{\mathrm{V}}_3=\frac{1}{1}:\frac{1}{2}:\frac{1}{3}\\ {\mathrm{V}}_1:{\mathrm{V}}_2:{\mathrm{V}}_3=6:3:2\end{array}$