Question

Two condensers of capacitance $4\mu F$ and $5\mu F$ are joined in series. If the potential difference across $5\mu F$ is $10V$, then the potential difference across $4\mu F$ condenser is :

• A. $22.5V$
• B. $10V$
• C. $12.5V$
• D. $25V$

Answer 1

The correct option is C $12.5V$

When two capacitors are in series $Q$ present on then is same
$\therefore Qon5\mu F$ is $Q=5\times {10}^{-6}\times 10$
$Q=5\times {10}^{-5}$
$\therefore Q$ on $4\mu F$ is $5\times {10}^{-5}$
$\therefore V=\frac{Q}{C}$
$V=\frac{5\times {10}^{-5}}{4\times {10}^{-6}}$
$V=12.5V$