Capacitance of Parallel Plate Capacitor Partially Filled with a Dielectric Medium.
Suppose the area of each plate of the capacitor is A, the distance between the plates d; t is the thickness of dielectric medium slab. Total potential difference between the plates is V.
The surface charge density on each plate,
σ = \(\frac{q}{A}\) ……………. (1)
The intensity of electric field in air between the plates :
E0 = \(\frac{q}{A}\) …………… (2)
and that in dielectric medium, E = \(\frac{\sigma}{\varepsilon_{0} K}\) ………….. (3)
Now from the definition of potential difference, the potential difference between the plates,
V = work done in displacing unit positive charge from negative plate to positive plate.
= Work done in carrying + 1C charge through (d – t) distance in air +t distance in dielectric medium.
Therefore capacity of the parallel plate capacitor partially filled with dielectric medium.
(iii) If there are n dielectric media of different constants and different thickness, as shown in adjoining figure, then
If no air space between the plates
