Question

Why dielectrics are used in capacitors?

Answer 1

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.
2. The equation for capacitance is given by, '

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

Use of dielectric in a capacitor

1. When a dielectric is inserted between the capacitor plates, the equation becomes
2. $C\text{'}=\frac{K{\epsilon }_{0}A}{d}$,where $K$ is the dielectric constant, ${\epsilon }_0$ is permittivity of free space, $A$ is the area of the plate, and $d$ is the distance between the plates. $\Rightarrow C\text{'}=KC$
3. The capacitance of a capacitor with a dielectric between its plates is $K$ times the original capacitance of the capacitor.

1. The capacitance of a capacitor can be increased by using a dielectric material.
2. The dielectric material reduces the electric field strength, the same amount of charge is obtained at a lower voltage.

Therefore, the dielectric is used in the capacitor.