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Halliday/Resnick/Walker

Fundamentals of Physics 8thedition

Classroom Response System Questions

Chapter 31 Electromagnetic Oscillationsand AC Current

Reading Quiz Questions

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31.2.1. Which one of the following quantities remains constant for a

given LC circuit

a! the energy store" in the capacitor

#! the energy store" in the in"uctor

c! the energy store" in the current flowing in the circuit

"! the sum of the energy store" in the capacitor an" that in the

in"uctor

e! the energy "issipate" in the circuit

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31.2.1. Which one of the following quantities remains constant for a

given LC circuit

a! the energy store" in the capacitor

#! the energy store" in the in"uctor

c! the energy store" in the current flowing in the circuit

"! the sum of the energy store" in the capacitor an" that in the

in"uctor

e! the energy "issipate" in the circuit

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31.3.1. $he te%t ma&es a comparison #etween an LC circuit an" a

#loc&'spring system. (n this analogy) the in"uctance correspon"sto which of the following parameters for the #loc&'spring system

a! mass

#! spring constant

c! velocity

"! position

e! spring potential energy

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31.3.1. $he te%t ma&es a comparison #etween an LC circuit an" a

#loc&'spring system. (n this analogy) the in"uctance correspon"sto which of the following parameters for the #loc&'spring system

a! mass

#! spring constant

c! velocity

"! position

e! spring potential energy

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31.3.2. Which one of the following is the correct e%pression for the

angular frequency of oscillation for an LC circuit

a!

#!

c!

"!

e!

LC =

LC =

1

LC =

1

LC=

2

LC

=

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31.3.2. Which one of the following is the correct e%pression for the

angular frequency of oscillation for an LC circuit

a!

#!

c!

"!

e!

LC =

LC =

1

LC =

1

LC=

2

LC

=

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31.*.1. Which one of the following statements concerning the electrical an"

magnetic energies store" in an LC circuit is false +ssume for the following

that , -.

a! $he ma%imum values of #oth the electric an" magnetic energies is Q2/2C.

#! $he electric energy is at its minimum when the magnetic energy is ero

/oules.

c! +t a time t) the sum of the electric an" magnetic energies is a constant equal

to Q2/2C.

"! $he electric energy varies in time with the factor) cos2t.

e! $he magnetic energy is at its ma%imum when the electric energy is ero

/oules.

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31.*.1. Which one of the following statements concerning the electrical an"

magnetic energies store" in an LC circuit is false +ssume for the following

that , -.

a! $he ma%imum values of #oth the electric an" magnetic energies is Q2/2C.

#! $he electric energy is at its minimum when the magnetic energy is ero

/oules.

c! +t a time t) the sum of the electric an" magnetic energies is a constant equal

to Q2/2C.

"! $he electric energy varies in time with the factor) cos2t.

e! $he magnetic energy is at its ma%imum when the electric energy is ero

/oules.

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31.0.1. Which of the following choices #est gives the #enefits! of

using +C over using C

a! $he length of wires is less relevant.

#! ower may #e transferre" over long "istances using higher voltage

an" low current.

c! $he potential "ifference may #e varie" using transformers.

"! +ny potential loss in resistive elements is negligi#le.

e! +ll of the a#ove answers are #enefits of +C over C.

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31.0.1. Which of the following choices #est gives the #enefits! of

using +C over using C

a! $he length of wires is less relevant.

#! ower may #e transferre" over long "istances using higher voltage

an" low current.

c! $he potential "ifference may #e varie" using transformers.

"! +ny potential loss in resistive elements is negligi#le.

e! +ll of the a#ove answers are #enefits of +C over C.

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31.0.2. (n an +C circuit) electrons are moving #ac& an" forth at a

frequency . $he signal that the electrons receive to change"irection comes from the generating station. What is the spee" of

that signal

a! v,xT) wherexis the "istance to a given electron an" Tis the

perio" of oscillation.

#! very close to the spee" of light

c! faster than the spee" of light

"! the "rift velocity of the electrons

e! the spee" of soun" in the metal wire

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31.0.2. (n an +C circuit) electrons are moving #ac& an" forth at a

frequency . $he signal that the electrons receive to change"irection comes from the generating station. What is the spee" of

that signal

a! v,xT) wherexis the "istance to a given electron an" Tis the

perio" of oscillation.

#! very close to the spee" of light

c! faster than the spee" of light

"! the "rift velocity of the electrons

e! the spee" of soun" in the metal wire

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31.4.1. Which of the following #est "escri#es the termforced

oscillations

a! oscillations requiring an applie" force

#! oscillations that occur at a frequency other than the natural

frequency of the circuit

c! oscillations that occur in the win"ings of the in"uctor within an

LRC circuit

"! oscillations that occur at the natural frequency of the circuit

e! oscillations that occur within the #attery of an LRC circuit

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31.4.1. Which of the following #est "escri#es the termforced

oscillations

a! oscillations requiring an applie" force

#! oscillations that occur at a frequency other than the natural

frequency of the circuit

c! oscillations that occur in the win"ings of the in"uctor within an

LRC circuit

"! oscillations that occur at the natural frequency of the circuit

e! oscillations that occur within the #attery of an LRC circuit

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31.5.1. +n alternating current is set up in an LRC circuit. 6or which

of the following circuit elements are the current an" voltage inphase

a! in"uctor only

#! resistor only

c! capacitor only

"! resistor an" capacitor only

e! in"uctor) resistor) an" capacitor

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31.5.1. +n alternating current is set up in an LRC circuit. 6or which

of the following circuit elements are the current an" voltage inphase

a! in"uctor only

#! resistor only

c! capacitor only

"! resistor an" capacitor only

e! in"uctor) resistor) an" capacitor

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31.5.2. +n alternating current is set up in an LRC circuit. 6or which

of the following circuit elements "oes the current lea" the voltage#y 7-

a! in"uctor only

#! resistor only

c! capacitor only

"! resistor an" capacitor only

e! in"uctor) resistor) an" capacitor

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31.5.2. +n alternating current is set up in an LRC circuit. 6or which

of the following circuit elements "oes the current lea" the voltage#y 7-

a! in"uctor only

#! resistor only

c! capacitor only

"! resistor an" capacitor only

e! in"uctor) resistor) an" capacitor

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31.5.3. +n alternating current is set up in an LRC circuit. 6or which

of the following circuit elements "oes the voltage lea" the current#y 7-

a! in"uctor only

#! resistor only

c! capacitor only

"! resistor an" capacitor only

e! in"uctor) resistor) an" capacitor

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31.5.3. +n alternating current is set up in an LRC circuit. 6or which

of the following circuit elements "oes the voltage lea" the current#y 7-

a! in"uctor only

#! resistor only

c! capacitor only

"! resistor an" capacitor only

e! in"uctor) resistor) an" capacitor

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31.5.*. What is the S( unit for capacitive reactance

a! fara"

#! mho

c! ohm

"! cor"el

e! reyn

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31.5.*. What is the S( unit for capacitive reactance

a! fara"

#! mho

c! ohm

"! cor"el

e! reyn

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31.5.8. Which one of the following choices is not a property of a

phasor

a! angular spee"

#! emf

c! length

"! pro/ection

e! rotation angle

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31.5.8. Which one of the following choices is not a property of a

phasor

a! angular spee"

#! emf

c! length

"! pro/ection

e! rotation angle

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31.5.0. When a capacitor is use" in an alternating current circuit) the current in the

capacitor is relate" to the voltage across the capacitor #y its capacitive

reactance) which "epen"s on the capacitance of the capacitor an" the frequency

of the generator. Which one of the following statements correctly "escri#es the

relationship #etween the capacitive reactance an" the frequency

a! $he capacitive reactance is "irectly proportional to the frequency.

#! $he capacitive reactance is "irectly proportional to the square of the frequency.

c! $he capacitive reactance is inversely proportional to the frequency.

"! $he capacitive reactance is inversely proportional to the square of the frequency.

e! $he capacitive reactance is "irectly proportional to the square root of the

frequency.

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31.5.0. When a capacitor is use" in an alternating current circuit) the current in the

capacitor is relate" to the voltage across the capacitor #y its capacitive

reactance) which "epen"s on the capacitance of the capacitor an" the frequency

of the generator. Which one of the following statements correctly "escri#es the

relationship #etween the capacitive reactance an" the frequency

a! $he capacitive reactance is "irectly proportional to the frequency.

#! $he capacitive reactance is "irectly proportional to the square of the frequency.

c! $he capacitive reactance is inversely proportional to the frequency.

"! $he capacitive reactance is inversely proportional to the square of the frequency.

e! $he capacitive reactance is "irectly proportional to the square root of the

frequency.

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31.5.4. When an in"uctor is use" in an alternating current circuit) the current in the

in"uctor is relate" to the voltage across the in"uctor #y its in"uctive reactance)

which "epen"s on the in"uctance of the in"uctor an" the frequency of the

generator. Which one of the following statements correctly "escri#es the

relationship #etween the in"uctive reactance an" the frequency

a! $he in"uctive reactance is "irectly proportional to the frequency.

#! $he in"uctive reactance is "irectly proportional to the square of the frequency.

c! $he in"uctive reactance is inversely proportional to the frequency.

"! $he in"uctive reactance is inversely proportional to the square of the frequency.

e! $he in"uctive reactance is "irectly proportional to the square root of the

frequency.

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31.5.4. When an in"uctor is use" in an alternating current circuit) the current in the

in"uctor is relate" to the voltage across the in"uctor #y its in"uctive reactance)

which "epen"s on the in"uctance of the in"uctor an" the frequency of the

generator. Which one of the following statements correctly "escri#es the

relationship #etween the in"uctive reactance an" the frequency

a! $he in"uctive reactance is "irectly proportional to the frequency.

#! $he in"uctive reactance is "irectly proportional to the square of the frequency.

c! $he in"uctive reactance is inversely proportional to the frequency.

"! $he in"uctive reactance is inversely proportional to the square of the frequency.

e! $he in"uctive reactance is "irectly proportional to the square root of the

frequency.

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31.7.1. Which of the following phrases #est "escri#es the term

impedance

a! the resistance to the movement of charge carriers

#! the resistance of a capacitor

c! the resistance of an in"uctor

"! the internal resistance of a #attery within an LRC circuit

e! the generalie" e%pression that com#ines all resistances within a

circuit

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31.7.1. Which of the following phrases #est "escri#es the term

impedance

a! the resistance to the movement of charge carriers

#! the resistance of a capacitor

c! the resistance of an in"uctor

"! the internal resistance of a #attery within an LRC circuit

e! the generalie" e%pression that com#ines all resistances within a

circuit

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31.7.2. 6or an RLC circuit in the limit of very high frequency) what is

the effective #ehavior of the capacitor an" the in"uctor in thecircuit

a! $he in"uctor acts li&e a very small resistance an" the capacitor acts

li&e a very large resistance.

#! $he in"uctor acts li&e a very large resistance an" the capacitor acts

li&e a very small resistance.

c! $he in"uctor acts li&e a very large resistance an" the capacitor actsli&e a very large resistance.

"! $he in"uctor acts li&e a very small resistance an" the capacitor acts

li&e a very small resistance.

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31.7.2. 6or an RLC circuit in the limit of very high frequency) what is

the effective #ehavior of the capacitor an" the in"uctor in thecircuit

a! $he in"uctor acts li&e a very small resistance an" the capacitor acts

li&e a very large resistance.

#! $he in"uctor acts li&e a very large resistance an" the capacitor acts

li&e a very small resistance.

c! $he in"uctor acts li&e a very large resistance an" the capacitor actsli&e a very large resistance.

"! $he in"uctor acts li&e a very small resistance an" the capacitor acts

li&e a very small resistance.

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31.7.3. What effect "oes the resistor in an RLC circuit have on the

circuit9s resonant frequency

a! $he resonant frequency is "etermine" #y the in"uctance an" the

capacitance) #ut not the resistance.

#! (ncreasing the resistance increases the resonant frequency.

c! ecreasing the resistance increases the resonant frequency.

"! (ncreasing the resistance "ecreases the resonant frequency.

e! ecreasing the resistance "ecreases the resonant frequency.

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31.7.3. What effect "oes the resistor in an RLC circuit have on the

circuit9s resonant frequency

a! $he resonant frequency is "etermine" #y the in"uctance an" the

capacitance) #ut not the resistance.

#! (ncreasing the resistance increases the resonant frequency.

c! ecreasing the resistance increases the resonant frequency.

"! (ncreasing the resistance "ecreases the resonant frequency.

e! ecreasing the resistance "ecreases the resonant frequency.

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31.7.*. Which of the following statements concerning resonance in an

RLC circuit is true

a! +t the resonant frequency) the rms current is at a minimum an" the

rms impe"ance is at a ma%imum.

#! +t the resonant frequency) the rms current is at a ma%imum an" therms impe"ance is at a minimum.

c! +t the resonant frequency) the rms current is at a ma%imum an" the

rms impe"ance is at a ma%imum.

"! +t the resonant frequency) the rms current is at a minimum an" the

rms impe"ance is at a minimum.

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31.7.*. Which of the following statements concerning resonance in an

RLC circuit is true

a! +t the resonant frequency) the rms current is at a minimum an" the

rms impe"ance is at a ma%imum.

#! +t the resonant frequency) the rms current is at a ma%imum an" therms impe"ance is at a minimum.

c! +t the resonant frequency) the rms current is at a ma%imum an" the

rms impe"ance is at a ma%imum.

"! +t the resonant frequency) the rms current is at a minimum an" the

rms impe"ance is at a minimum.

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31.1-.1. Which of the following choices gives the amount of power

use" #y a capacitor in an ac circuit

a! IrmsXC

#! IrmsXC2

c! VrmsIrms2

"! VrmsXC

e! $he power use" #y the capacitor is equal to ero watts.

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31.1-.1. Which of the following choices gives the amount of power

use" #y a capacitor in an ac circuit

a! IrmsXC

#! IrmsXC2

c! VrmsIrms2

"! VrmsXC

e! $he power use" #y the capacitor is equal to ero watts.

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31.1-.2. (n a series RLC circuit) the average power is given #y

. What is the name given to the term cos

a! phase factor

#! force term

c! power factor

"! energy "eterminator

e! rms term

cos

rmsrms

VIP =

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31.1-.2. (n a series RLC circuit) the average power is given #y

. What is the name given to the term cos

a! phase factor

#! force term

c! power factor

"! energy "eterminator

e! rms term

cos

rmsrms

VIP =

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31.11.1. Which of the following is the primary #enefit of impe"ance

matching

a! ma%imum transfer of energy

#! ma%imum resistive loa"

c! same time constant

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31.11.1. Which of the following is the primary #enefit of impe"ance

matching

a! ma%imum transfer of energy

#! ma%imum resistive loa"

c! same time constant

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31.11.2. (n a well'"esigne" transformer with an iron core) the secon"ary coil has

twice as many turns as the primary coil. Which one of the following statements

concerning this transformer is true

a! $he flu% that passes through each turn of the primary coil is twice the flu% that

passes through the secon"ary coil.

#! $he effect of the iron core is to re"uce the magnetic fiel" passing through thecoils.

c! $he in"uce" emf generate" in the secon"ary coil is twice as large as that

generate" in the primary coil.

"! $his is a step "own transformer #ecause the current in the secon"ary coil is less

than that in the primary coil.

e! $his &in" of transformer is typically use" #etween a power transmission line an"

a resi"ence.

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31.11.2. (n a well'"esigne" transformer with an iron core) the secon"ary coil has

twice as many turns as the primary coil. Which one of the following statements

concerning this transformer is true

a! $he flu% that passes through each turn of the primary coil is twice the flu% that

passes through the secon"ary coil.

#! $he effect of the iron core is to re"uce the magnetic fiel" passing through thecoils.

c! $he in"uce" emf generate" in the secon"ary coil is twice as large as that

generate" in the primary coil.

"! $his is a step "own transformer #ecause the current in the secon"ary coil is less

than that in the primary coil.

e! $his &in" of transformer is typically use" #etween a power transmission line an"

a resi"ence.