Role of dielectric in capacitor

they are insulators

satty lavanyatel me about the dielectrics in capacitors?

What part of the article: <a href="https://en.wikipedia.org/wiki/Dielectric" target="_blank" rel="noopener noreferrer">Dielectric</a> is difficult for you to understand?

The main role of dielectrics in capacitors is to increase the value of capacitance of the capacitor. We all pretty well know that C=EA\D where E-permittivity. We know that the permittivity is the product of permittivity of free space and the permittivity of the medium. When air is the medium the permittivity of medium is unity but as dielectric is used in a capacitor the permittivity of medium is greater than unity and obviously the product is greater and thus the capacitance is greater. "K" I suppose she asks about the specific role of Dielectrics in Capacitors and not the literal "Dielectric".

we can divided dielectric in to class as like follows

​•Classes of Dielectrics – Two basic groups (Class 1 and Class 2) are used in the manufacture of ceramic chip capacitors.​Class 1:dielectrics display the most stable characteristics of frequency, voltage, time and temperature coefficients (TC). TC is expressed as a % of capacitance change from a reference or parts per million per degree C (ppm/ºC). ​ ​ Class 2 :dielectrics offer much higher dielectric constants but with less stable properties with temperature, voltage, frequency, and time. TC is expressed as a % change from a reference (+- 15% over some range of temperature

you can also know more about this capacitor with properties as follows in below link
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hey you can see the types of dielectric with temperature on following link
#-Link-Snipped-# Constants.htm