Question

A series combination of three capacitors of capacities $1\, \mu F ,\, 2\, \mu F$ and $8\, \mu F$ is connected to a battery of e.m.f. $13$ volt. The potential difference across the plates of $2\, \mu F$ capacitor will be

• A. 1 V
• B. 8 V
• C. 4 V
• D. $\frac{13}{3} V$

Answer 1

Answer: (C)

$\frac{1}{C_{e q}}=\frac{1}{1}+\frac{1}{2}+\frac{1}{8}$
$\Rightarrow C_{e q}=\frac{8}{13} \mu F$
Total charge, $Q=C_{e q} V=\frac{8}{13} \times 13=8\, \mu C$
Potential difference across $2\, \mu F$ capacitor
$=\frac{8}{2}=4\, V$