When a certain air-?lled parallel-plate capacitor is connected across a battery, it acqquires a charge (on each plate) of magnitude 131 µC. While the battery connection is maintained, a dielectric slab is inserted into the space between the capacitor plates and completely ?lls this region. This results in the accumulation of an additional charge of 308 µC on each plate.
What is the dielectric constant of the slab?