Capacitor and Capacitance

IMPORTANT

Capacitor and Capacitance: Overview

This topic covers concepts, such as, Isolated Spherical Capacitor, Capacitor and Its Capacitance, Concentric Spheres as a Capacitor & Long Coaxial Cylindrical Capacitor etc.

Important Questions on Capacitor and Capacitance

EASY
IMPORTANT

When the charge on a capacitor increases keeping geometry the same

EASY
IMPORTANT

A parallel plate capacitor is first charged and then disconnected from the battery and then a dielectric slab is introduced between the plates. The quantity that remains unchanged is

MEDIUM
IMPORTANT

A circuit has a section AB, shown in the figure. The emf of the source is equal to 10 V and the capacitance of capacitor are equal to C1=1.0 μF and C2=2.0 μF. If the potential difference between points A and B, ϕA-ϕB=5.0 V, then the voltages V1 and V2 across each capacitors, C1 and C2, respectively, are

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HARD
IMPORTANT

A capacitor of capacitance 10 μF is charged to a potential 50 V with a battery. The battery is now disconnected and an additional charge 200 μC is given to the positive plate of the capacitor. The potential difference across the capacitor will be

EASY
IMPORTANT

Two uncharged capacitors are charged with a battery of E volt. The ratio of charges produced on these capacitors Q1Q2 will be

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MEDIUM
IMPORTANT

The equivalent capacitance of three capacitors of capacitance C1,C2and C3 are connected in parallel is 12 units and product C1·C2·C3=48 units. When the capacitors C1and C2 are connected in parallel, the equivalent capacitance is 6 units. Then the capacitances are

EASY
IMPORTANT

Which one is the SI unit of capacitance?

MEDIUM
IMPORTANT

An air capacitor of capacity C=10 μF is connected to a constant voltage battery of 12 V. Now the space between the plates is filled with a liquid of dielectric constant 5. The additional charge that flows now, from the battery to the capacitor is:

MEDIUM
IMPORTANT

Calculate the energy stored in a sphere of radius 4 cm if it is charged to 300 volt.

MEDIUM
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Find the potential difference between these two plates.

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EASY
IMPORTANT

Two spherical conductors A and B of radii a and bb>a  are placed concentrically in air, The two are connected by a copper wire as shown in figure. Then the equivalent capacitance of the system is :-

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HARD
IMPORTANT

A parallel plate capacitor consists of two square plates, each edge a. There is a dielectric slab of dielectric constant K in the shape of a cylinder of parabolic cross-section between the plates. The figure shows the cross-section parallel to an edge of the plate.The capacitance of the capacitor is P100 fF, find P.

Take K=2, a=1 mm. Given0a/2dxa2-x2a=1.2465

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MEDIUM
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The quantity X=ε0LVt : ε0 is the permittivity of free space, L is length, V is potential difference and t is time. The dimensions of X are same as that of :-

MEDIUM
IMPORTANT

A parallel plate air capacitor has a capacitance C. When it is half filled with a dielectric of dielectric constant 5. The percentage increase in the capacitance will be :- Question Image

MEDIUM
IMPORTANT

A circuit has a section AB, shown in the figure. The emf of the source is equal to 10 V and the capacitors capacitance are equal to C1=1.0 μF and C2=2.0 μF. If the potential difference between points A and B, ϕA-ϕB=5.0 V, then the voltages V1 and V2 across each capacitors, C1 and C2, respectively, are

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EASY
IMPORTANT

A thin metal plate P is inserted between the plates of a parallel-plate capacitor of capacitance C in such a way that its edges touch the two plates. The capacitance now becomes
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EASY
IMPORTANT

The radii of two spherical conductors are in ratio 1:2. The ratio of their capacitance is.

HARD
IMPORTANT

Calculate the capacitance of a spherical conductor of radius R1. It has an adjacent concentric layer of dielectric of permittivity K and outside radius R2. The system is isolated.k=14πε0

MEDIUM
IMPORTANT

A parallel plate capacitor, a spherical capacitor and cylindrical capacitor is charged by identical battery and then battery is removed from the each capacitor. Consider the following situations

(i) separation between the plates of parallel plate capacitor is reduced

(ii) radius of the outer spherical shell of the spherical capacitor is increased

(iii) radius of the outer cylinder of cylindrical capacitor is increased Which of the following is correct ?

EASY
IMPORTANT

Two charged capacitors with their outer plates fixed and inner plates connected by a spring of force constant k have a charge of q on them. Find the extension in the spring at equilibrium.
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