A parallel-plate air capacitor has a plate area of 100cm³ 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 new potential difference between plates of the capacitor.

115 V

$V'= \frac{V}{K} = \frac{300V}{2.6} = 115V$