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Corona loss does not depends on-

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Important Questions on Capacitance and Capacitors

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

When a soap bubble is charged?

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

A hollow conducting sphere is placed in an electric field produced by a point charge placed at $P$ as shown in figure. Let $V_{A}, V_{B}, V_{C}$ be the potentials at points $A, B$ and $C$ , respectively. Then

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HARD

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

A cylindrical capacitor is filled with two cylindrical layers of dielectric with permittivities

ε_{1}

and

ε_{2} .

The inside radii of the layers are equal to

R_{1}

and

R_{2} (R_{2} > R_{1})

. The maximum permissible values of electric field strength are equal to

E_{1 m}

and

E_{2 m}

, for these dielectrics. At what relationship between

ε_{1} R_{1}

and

E_{m}

, will the voltage increase result in the field strength reaching the breakdown value, for both dielectrics simultaneously?

EASY

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

Capacitance of a capacitor _____ when a dielectric is introduced between its two plates.

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

A parallel plate capacitor is made of two circular plates separated by a distance of

5 mm

and with a dielectric of a dielectric constant

2.2

between them. When the electric field in the dielectric is

3 \times 10^{4} V m^{- 1}

, the charge density of the positive plate will be close to

MEDIUM

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

A parallel plate capacitor has a dielectric slab of dielectric constant $K$ between its plates that covers $\frac{1}{3}$ of the area of its plates as shown in the figure. The total capacitance of the capacitor is $C$ while that of the portion with dielectric in between is $C_{1}$ . When the capacitor is charged, the plate area covered by the dielectric gets charge $Q_{1}$ and the rest of the area gets charge $Q_{2}$ . Choose the correct option ignoring edge effects.

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

What is the largest charge a metal ball of $1 mm$ radius can hold? (Dielectric strength of air is $3 \times 10^{6} V m^{- 1}$ )

MEDIUM

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

The dielectric constant decreases if the temperature is increased. Explain this in terms of polarization of the material.

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

Dielectric constant being a force of two _____ quantities is a pure number.

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

If dielectric constant and dielectric strength be denoted by

K

and

X

respectively then a material suitable for use as dielectric in a capacitor must have:-

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

Which of the following set of characteristics of a material is suitable for using it as a dielectric in a capacitor?

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

A parallel plate capacitor of plate area

A

and plate separation

d

is charged to potential difference

V

and then the battery is disconnected. A slab of dielectric constant

K

is then inserted between the plates of the capacitor so as to fill the space between the plates. If

Q, E

and

W

denotes respectively the magnitude of charge on each plate, the electric field between the plates (after the slab is inserted) and work done on the system, in question, in the process of inserting the slab, then which of the following statement is wrong ?

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

The dielectric material between the plates of a capacitor provides _____ (mount type/ mechanical/ ground) support to the attracting plates of a capacitor.

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

Guess a possible reason why water has a much greater dielectric constant

(= 80)

than say, mica

(= 6) .

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

The corona loss on a particular system at

50 Hz

1 \frac{KW}{km}

per phase. The corona loss at

60 Hz

in the same system would be

MEDIUM

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

A parallel plate capacitor of area A, plate separation

d

and capacitance

C

is filled with three different dielectric materials having dielectric constants

k_{1}, k_{2}

and

k_{3}

as shown in figure. If a single dielectric material is to be used to have the same capacitance

C

in this capacitor, then the dielectric constant

k

is given by

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MEDIUM

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

If dielectric constant and dielectric strength be denoted by

K

and

X

respectively, then a material suitable for use as a dielectric in a capacitor must have

HARD

Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

Assertion: A spark occurs sometimes when an electric iron is switched off.

Reason: The sparking is due to large self-induced emf in the circuit, during make.

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

The Corona effect can be minimized by increasing-

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Physics>Electricity and Magnetism>Capacitance and Capacitors>Dielectric Breakdown and Corona Discharge

The dielectric material between the plates of a capacitor increases _____ (maximum operating voltage/ electric field) of the capacitor.

Corona loss does not depends on-

Important Questions on Capacitance and Capacitors

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