A capacitor is an energy storage device. When fully charged, an electric field e

Question

A capacitor is an energy storage device. When fully charged, an electric field exists between the plates. Suppose an insulating material known as a dielectric were placed between the plates. It is seen that the amount of energy increases inside the capacitor. The permittivity of this medium is different than that of air. Assume that with or without the dielectric the capacitor stays connected with the power supply that charged it. You may assume the power supply is set at 12 V for instance. Given this information, the best possible definition for permittivity would be:

a.The ability to keep the plates pushed apart when fully charged.

b.The rate in which the electric field can be expelled from the capacitor.

c.The ability of a medium to store electrical energy within an electric field.

d.The ability of a medium to convert from an insulator to an electrical conductor.

I want to know why is 'c' the correct answer.

fully explain for points

Explanation / Answer

when you add a dielectric, it increases the capcitance (does not depend upon the voltage supplied).

so charge increases

if charge increases, electric field strength increases

and the increased electric field strength means stored energy increases

so option C is the correct one.

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