Parallel plate capacitor: It consist of two large plane parallel conducing plate separated by small distance.

Let A = area of each plate

d = distance between two paltes

± σ = uniform surface charge densities on the two plates

 ± θ = ±σA = total charge on each plate.

In the outer region above the upper plate and below the lower plate the electric field due to the two charge plates cancel out. The not field is zero.

E= σ/2∈₀ - σ/2∈₀ =0

For a uniform electric field P.d. between the plate equals to the electric field * distance between the plates.

V=E*d=σ/∈₀

Capacitance of a parallel plate capacitor is

Factors on which the capacitance of parallel plate capacitor depends:

1. Area of plates A i.e. C ∝ A
2. Distance between the plate d i.e. C ∝ 1/d
3. Permittivity of the medium between the two plates C ∝ ∈