Physics - Electrostatics Question with Solution | TestHub

The minimum value of effective capacitance is get in series combination.

Now, the equivalent capacitance,

$\frac{1}{C_{eq}}=\frac{1}{1}+\frac{1}{2}+\frac{1}{4}$

$\frac{1}{C_{eq}}=\frac{4+2+1}{4}$

$\frac{1}{C_{eq}}=\frac{7}{4}$

$C_{eq}=\frac{4}{7}\mathrm{ p}\mathrm{F}$