Question

When two identical capacitors are connected in series, the equivalent capacitance is $7.5\mu F.$ What is the equivalent capacitance when they are connected in parallel?

Answer 1

In series combination-

$\frac{1}{C}=\frac{1}{C_1}+\frac{1}{C_2}$

$⟹C_{eq}=\frac{C}{2}=7.5$

$⟹C=15\mu F$

Now, in parallel combination-

$C_{eq}=C_1+C_2=2C$

$⟹C_{eq}=30\mu F$