Question

Two capacitors of $3\, \mu F$ and $6\, \mu F$ are connected in series across a potential difference of $120\, V$. Then the potential difference across $3 \,\mu F$ capacitor is

• A. $50\, V$
• B. $60\, V$
• C. $70\, V$
• D. $80\, V$

Answer 1

Answer: (D)

Here, $\frac{1}{C_{S}}=\frac{1}{3}+\frac{1}{6}=\frac{1}{2}$
$C_{S}=2\,\mu F$
$Q=C_{S}V=2\times120$
$=240\,\mu C$
$V_{1}=\frac{Q}{C_{1}}=\frac{240}{3}$
$=80\,V$