Question

Three condensers $1\mu F$, $2\mu F$ and $3\mu F$ are connected in series to a potential difference of $330$ volt. The potential difference across the plates of $3\mu F$ is:

• A. $180V$
• B. $300V$
• C. $60V$
• D. $270V$

Answer 1

The correct option is C $60V$

$\frac{1}{C_{eff}}=\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_1}$

$\frac{1}{C_{eff}}=\frac{1}{1}+\frac{1}{2}+\frac{1}{3}$

$\frac{1}{C_{eff}}=\frac{6+3+2}{6}$

$C_{eff}=\frac{6}{11}$

$Q=\frac{6}{11}\times 33$

$Q=180$

$\to$ Charge present on capacitor plates in series must be equal

$\therefore Q=CV$

$V=\frac{Q}{C}\Rightarrow V=\frac{180}{3}=60V$