Explain difference in behaviour of a conductor and dielectric in presence of external electric field

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2. Electric Potential and Capacitance

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Explain the difference in the behaviour of a conductor and dielectric in the presence of external electric field.

Option A

Option B

Option C

Option D

Solution

There are charge carriers in conductor.

When a conductor is subjected to external electric field. The free charge carriers move and charge distribution in the conductor adjusts itself in such a way that the electric field due to the induced charges $\left(E_{i n}\right)$ opposes the external field $\left(E_{0}\right)$ within the conductor. This happen until the two fields cancel each other and the net electrostatic field in the conductor is zero.

$\therefore \mathrm{E}_{0}+\mathrm{E}_{\text {in }}=0$

In a dielectric free movement of charges is not possible but the external field induces dipole moment by stretching or reorienting molecules of the dielectric.

The collective effect of all the molecular dipole moments is net charges on the surface of the dielectric which produce a field that opposes the external field. Hence external electric field reduces.

$\therefore \mathrm{E}_{0}+\mathrm{E}_{\mathrm{in}} \neq 0$

The extent of the effect depends on the nature of the dielectric.

The behaviour of a conductor and dielectric in the presence of external electric field are shown as in below.

Dielectric : "Dielectric is such a substance that it does not allow the charges to pass through it but allows the electric force on charged to each other.

Actually is an insulator that can be polarized by limited displacement of charges.

Standard 12

Physics

The potential gradient at which the dielectric of a condenser just gets punctured is called

easy

Two identical parallel plate capacitors, of capacitance $C$ each, have plates of area $A$, separated by a distance $d$. The space between the plates of the two capacitors, is filled with three dielectrics, of equal thickness and dielectric constants $K_1$ , $K_2$ and $K_3$ . The first capacitor is filled as shown in fig. $I$, and the second one is filled as shown in fig. $II$. If these two modified capacitors are charged by the same potential $V$, the ratio of the energy stored in the two, would be ( $E_1$ refers to capacitor $(I)$ and $E_2$ to capacitor $(II)$)

hard

(JEE MAIN-2019)

Define dielectric constant.

medium

Two capacitors of capacities $2 {C}$ and ${C}$ are joined in parallel and charged up to potential ${V}$. The battery is removed and the capacitor of capacity $C$ is filled completely with a medium of dielectric constant ${K}$. The potential difference across the capacitors will now be

medium

(JEE MAIN-2021)

In a capacitor of capacitance $20\,\mu \,F$, the distance between the plates is $2\,mm$. If a dielectric slab of width $1\,mm$ and dielectric constant $2$ is inserted between the plates, then the new capacitance is……$\mu \,F$

medium

Explain the difference in the behaviour of a conductor and dielectric in the presence of external electric field.

Solution

Similar Questions

The potential gradient at which the dielectric of a condenser just gets punctured is called

Define dielectric constant.

Two capacitors of capacities $2 {C}$ and ${C}$ are joined in parallel and charged up to potential ${V}$. The battery is removed and the capacitor of capacity $C$ is filled completely with a medium of dielectric constant ${K}$. The potential difference across the capacitors will now be

In a capacitor of capacitance $20\,\mu \,F$, the distance between the plates is $2\,mm$. If a dielectric slab of width $1\,mm$ and dielectric constant $2$ is inserted between the plates, then the new capacitance is……$\mu \,F$

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