A parallel-plate air capacitor has a plate area of 100cm2 and separation 5mm. A potential difference of 300V is established between its plates by a battery. After disconnecting a battery, the space between the plates is filled by ebonite (K = 2.6). Find out initial and final capacitances of the capacitor.
Answer & explanation
Correct answer: option 2
$ C = \frac{\epsilon_0 A}{d} = \frac{8.85\times 10^{-12}\times 10^{-2}}{5\times 10^{-3}}= 1.77\times 10^{-11}$
$ C' = KC = 4.6\times 10^{-11}$