Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. The plates of a parallel plate capacitor are charged to a potential of $200V$ . Now, a dielectric slab of thickness $4mm$ is inserted between its plates and to maintain the same potential difference between the plates of the capacitor, the distance between the plates is increased by $3.2mm$ . The dielectric constant of the slab is

NTA AbhyasNTA Abhyas 2022

Solution:

$\frac{\epsilon _{0} A}{d} \, = \, \frac{\epsilon _{0} A}{d^{′} - t + \frac{t}{K}}$
$\Rightarrow d=d^{′}-t+\frac{t}{K}$
$\Rightarrow d^{′}-d=t\left(1 - \frac{1}{K}\right)$
Here, $d^{′}-d=3.2 \, mm, \, t=4 \, mm$
$\therefore 3.2=4\left(1 - \frac{1}{K}\right)$
$\Rightarrow \frac{3 .2}{4}=1-\frac{1}{K}$
$\Rightarrow 1-\frac{1}{K}=\frac{4}{5}$
$\therefore K=5$