Question

The difference in the effective capacity of two similar capacitors when joined in series and then in parallel is $6\mu F$. The capacity of each capacitor is :

• A. $2\mu F$
• B. $4\mu F$
• C. $8\mu F$
• D. $16\mu F$

Answer 1

Answer: (B)

$4\mu F$

Let the capacitance of each capacitor be $C$

For series combination : $\frac{1}{C_s}=\frac{1}{C}+\frac{1}{C}$

$⟹C_s=\frac{C}{2}$

For parallel combination : $C_p=C+C$ $⟹C_p=2C$

Given : $C_p-C_s=6\mu F$

$\Rightarrow$ $2C-\frac{C}{2}=6\mu F$

$⟹C=4\mu F$