Energy Stored in a Capacitor and Energy Stored in Electric Field

IMPORTANT

Energy Stored in a Capacitor and Energy Stored in Electric Field: Overview

This topic covers concepts, such as, Energy Stored in the Electric Field, Energy Density in Electric Field, Energy in Constant Electric Field & Energy in Variable Electric Field etc.

Important Questions on Energy Stored in a Capacitor and Energy Stored in Electric Field

MEDIUM
IMPORTANT

An uncharged capacitor of capacitance 100 μF is connected to a battery of emf 20 V at t=0 through a resistance of 10 Ω, then:

(i) The maximum rate at which energy is stored in the capacitor

(a) 10 J s-1

(b)  20 J s-1

(c) 40 J s-1

(d) 5 J s-1

(ii) Time at which the rate has this maximum value

(a) (4ln2) ms

(b) (2ln2) ms

(c) (ln2) ms

(d) (3ln2) ms

EASY
IMPORTANT

A 600 pF capacitor is charged by 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF capacitor. Electrostatic energy lost in the process is _____ μJ.

EASY
IMPORTANT

In the circuit shown, the energy stored in the capacitor is n μJ. The value of n is _____.

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MEDIUM
IMPORTANT

A parallel plate capacitor of capacitance 2 F is charged to a potential V. The energy stored in the capacitor is E1. The capacitor is now connected to another uncharged identical capacitor in parallel combination. The energy stored in the combination is E2. The ratio E2E1 is

MEDIUM
IMPORTANT

Find the energy stored in the capacitor in the given circuit.

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MEDIUM
IMPORTANT

A parallel plate capacitor of capacitance 8 μF is connected to a 20 V battery and is allowed to charge completely. The battery is then disconnected and a dielectric material of dielectric constant 8 is introduced between the plates of the capacitor. The energy dissipated in this process is

EASY
IMPORTANT

10 μF capacitor is charged by 200 V. The heat lost in charging it is

EASY
IMPORTANT

If capacitance is increased by 2 times what will be the energy? Give the answer for vice versa case also?

MEDIUM
IMPORTANT

Calculate the equivalent capacity of the system as shown in the figure. What is the energy stored in the system if voltage applied is 500 V.

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EASY
IMPORTANT

The capacitance of system is C. If key is closed, the total energy loss is equal to:

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MEDIUM
IMPORTANT

The total electrostatic energy stored in both the capacitors (in μJ) is

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MEDIUM
IMPORTANT

The plates of a parallel plate capacitor with no dielectric are connected to a voltage source. Now a dielectric of dielectric constant K is inserted to fill the whole space between the plates with voltage with voltage source remaining connected to the capacitor. Then

MEDIUM
IMPORTANT

A capacitor of capacitance 5 μF is connected to a source of constant emf of 200 V for a long time, then the switch was shifted to contact 1 from contact 2 . The amount of heat generated in the 500 Ω resistance is H. Find value of 16H (in J).

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EASY
IMPORTANT

In the given circuit, find the heat generated if switch S is closed.

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MEDIUM
IMPORTANT

Two capacitors one of capacity C and the other of capacity C2, are connected to a V volt battery, as shown. Work done by the battery in charging of this combination will be:

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HARD
IMPORTANT

In the circuit shown switch is placed in position-1 till the capacitor is charged to half of the maximum possible charge in this situation.

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Now the switch S is placed in position-2. The maximum energy lost by the circuit after S is placed in position-2 is x8CE2. Find x.

EASY
IMPORTANT

The heat generated through 2 Ω and 8 Ω resistances separately, when a condenser of 200 μF capacity charged to 200 V is discharged one by one, will be

EASY
IMPORTANT

A parallel-plate capacitor of capacitance 100 μF is connected to a power supply of 200 V. A dielectric slab of dielectric constant 5 is now inserted into the gap between the plates. Find the change in the electrostatic energy (in J) of the electric field in the capacitor.

MEDIUM
IMPORTANT

Three identical large metal plates of area A are at distances 2d and d(d length of plates) from each other (refer figure). Metal plate A is uncharged, while metal plates B and C have respective charges +q and -q. Metal plates A and C are connected by switch K through a wire. The heat produced after closing the switch K is q2 dPε0 A. Find P.

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