2. Electric Potential and Capacitance
hard

The parallel combination of two air filled parallel plate capacitors of capacitance $C$ and $nC$ is connected to a battery of voltage, $V$. When the capacitor are fully charged, the battery is removed and after that a dielectric material of dielectric constant $K$ is placed between the two plates of the first capacitor. The new potential difference of the combined system is

A

$\frac{V}{{K + n}}$

B

$V$

C

$\frac{{\left( {n + 1} \right)\,V}}{{\left( {K + n} \right)}}$

D

$\frac{{nV}}{{K + n}}$

(JEE MAIN-2019)

Solution

After fully charging, battery is disconnected.

Total chare of the system $=\mathrm{CV}+\mathrm{nCV}$

$=(n+1) C V$

After the insertion of dielectric of constant $\mathrm{K}$ New potential (common) $\mathrm{V}_{\mathrm{c}}=\frac{\text { Total charge }}{\text { Total capacitance }}$

$=\frac{(n+1) C V}{K C+n C}=\frac{(n+1) V}{K+n}$

Standard 12
Physics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.