The capacitance of a parallel plate capacitor without any medium between its plates is given by

When a dielectric completely fills the space between the plates of the capacitor, the capacitance increases K times, where K is the dielectric constant (relative permitivity) of the dielectric.

If a dielectric slab of thickness t (<d) is introduced between the plates, the capacitance becomes

OR

OR

In each case the capacitance increases with the introduction of a dielectric in between the plates

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