Effects of Dielectrics in Capacitors

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Basic Knowledge of Effect of Dielectric on Capacitance of Parallel Plate Capacitor

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Important Questions

A parallel plate capacitor is charged by a battery, which is then disconnected. A dielectric slab is then inserted in the space between the plates. Explain what changes, if any, occur in the values of
(i) capacitance.
(ii) potential difference between the plates.
(iii) electric field between the plates.
(iv) the energy stored in the capacitor.

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A parallel plate capacitor of area A, plate separation and capacitance is filled with three different dielectric materials having dielectric constants as shown. If a single dielectric material is to be used to have the same capacitance in this capacitor then its dielectric constant is given by

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A slab of material of dielectric constant K has the same area as the plates of a parallel plate capacitor but has thickness , where d is the distance between plates. How is the capacitors changed when the slab is inserted between the plates?

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Derive the expression for the capacitance of a parallel plate capacitor.

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A parallel plate capacitor has plates of area 'A' separated by distance 'd' between them. It is filled with a dielectric which has a dielectric constant that varies as where 'x' is the distance measured from one of the plates. If , the total capacitance of the system is best by the expression:

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A parallel plate capacitor with air between the plates has a capacitance of 8 pF (1pF = F). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant 6?

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A parallel plate capacitor is charged by a battery.
The battery is disconnected and a dielectric slab is inserted to completely fill the space between the plates. 
How will (i) its capacitance, (ii) electric field between the plates and (iii) energy stored in the capacitor be affected ? Justify your answer giving necessary mathematical expressions for each case.

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Predict the polarity of the capacitor in the situation described by figure

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The potential difference between the two plates of a parallel plate capacitor is constant. When air between the plates is replaced by dielectric material, the electric field intensity :

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A parallel plate air capacitor is charged to a potential difference of V volts. After disconnecting the charging battery the distance between the plates of the capacitor is increased using an insulating handle. As a result the potential difference between the plates:

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