Question

A paper-filled capacitor is charged to a potential difference of 2.6 V and then disconnected from the charging circuit. The dielectric constant of the paper is 3.7. Keeping the plates insulated, the paper filling is withdrawn, allowing air to fill the capacitor instead. Find the resulting potential difference of the capacitor.

Answer 1

Given:

Potential difference between capacitor plates = 2.6 V

Dielectric constant of paper , K = 3.7

Solution:

When air is filled, let the potential difference between capacitor plate be V'

Now, after being disconnected from the battery, the charge stored in the capacitor will remain constant

And when dielectric is introduced between the capacitor plates, the potential difference will be reduced by k times a:

V = $\frac{V'}{K}$

Therfore, V' = KV = 3.7 × 2.6 = 9.62 V

The resulting potential difference of the capacitor, V' = 9.62 V