Question

A parallel plate capacitor of capacitance $10\mu F$ is connected across a battery of e.m.f. $5mV$. Now, the space between the plates of the capacitor is filled with a dielectric material of dielectric constant $K=5$. Then, the charge that flows through the battery, till equilibrium is reached is

• A. $250\mu C$
• B. $250nC$
• C. $200nC$
• D. $200\mu C$

Answer 1

The correct option is C $200nC$

Case-I

$Q_1=10\mu F\times 5mV$
$Q_1=10\times {10}^{-6}\times 5\times {10}^{-3}C$
$Q_1=50\times {10}^{-9}C$

Case-II

$Q_2=5\times 10\mu F\times 5mV$
$Q_2=5\times 10\times {10}^{-6}\times 5\times {10}^{-3}C$
$Q_2=250\times {10}^{-9}C$
Now, $\begin{array}{cc}{Q}_2-Q_1& =250\times {10}^{-9}-50\times {10}^{-9}C\\ Q_2-Q_1& =200\times {10}^{-9}C\\ & =200nC\end{array}$