Question

A parallel plate condenser has conducting plates of radius $12cm$ seperated by a distance of $5mm$. It is charged with a constant charging current of $0.16A$. the rate at which the potential difference between the plates change is:

• A. $1\times {10}^9{Vs}^{-1}$
• B. $2\times {10}^{10}{Vs}^{-1}$
• C. $3\times {10}^{12}{Vs}^{-1}$
• D. $2\times {10}^9{Vs}^{-1}$

Answer 1

The correct option is D $2\times {10}^9{Vs}^{-1}$

$q=CV$
$I=C\frac{dv}{dt}$
$\frac{dv}{dt}=\frac{I}{C}$
$C=\frac{\pi \times 144\times 8.85\times {10}^{\Omega }}{{10}^4\times 5{\times }^{-3}}=8\times {10}^{-11}$
$\frac{dv}{dt}=\frac{0.16}{8}\times {10}^{11}=2\times {10}^9$