Question

Why do dielectrics increase capacitance ?

Answer 1

Capacitance

Capacitance is defined as the quantity of charge required to raise the potential of a conductor by one unit in the given environment.

The equation for capacitance is given by, '

$C=\frac{{\epsilon }_{0}A}{d}$

Use of dielectric in a capacitor

When a dielectric is inserted between the capacitor plates, the equation becomes

$C\text{'}=\frac{K{\epsilon }_{0}A}{d}$

where $K$ is the dielectric constant, ${\epsilon }_0$ is permittivity of free space, $A$ is the area of the plate, $d$ is the distance between the plates.

$\Rightarrow C\text{'}=KC$

1. The capacitance of a capacitor with dielectric between its plates is $K$ times the original capacitance of the capacitor.
2. The capacitance of a capacitor can be increased by using a dielectric material.
3. The dielectric material reduces the electric field strength, and the same amount of charge is obtained at a lower voltage.
4. Dielectric placed between the capacitor plated reduces electric field strength between the capacitor plates, which results in small voltage between the capacitor plates for the same charge. The capacitor stores more charge for smaller voltage.

Therefore, capacitance increase $K$ times.