Clicker Chapter 30

8/3/2019 Clicker Chapter 30

1/74

Chapter 30: Maxwells Equations and

Electromagnetic Waves

Section 30-1: Maxwells DisplacementCurrent


2/74

A parallel-plate capacitor has closely spacedcircular plates of radius R= 2.00 cm.

Charge is flowing onto the positive plate atthe rate I= dQ/dt= 1.36 A. The magneticfield at a distance r= 2.00 cm from the axis

of the plates is approximatelyA. 136 mT

B. 256 mT

C. 16.5 mT

D. 457 mT

E. 88.3 mT


3/74

A parallel-plate capacitor has closely spacedcircular plates of radius R= 2.00 cm.

Charge is flowing onto the positive plate atthe rate I= dQ/dt= 1.36 A. The magneticfield at a distance r= 2.00 cm from the axis

of the plates is approximatelyA. 136 mT

B. 256 mT

C. 16.5 mT

D. 457 mT

E. 88.3 mT


4/74

Charge is flowing onto one plate of aparallel-plate capacitor and off the other

plate at a rate of 5.00 A. The rate at whichthe electric field between the plates ischanging is approximately

A. 5.65 1011 N m2/(C s)

B. 11.3 1011 N m2/(C s)

C. 2.45 1011 N m2/(C s)D. 12.4 1011 N m2/(C s)

E. 1.76 1011 N m2/(C s)


5/74

Charge is flowing onto one plate of aparallel-plate capacitor and off the other

plate at a rate of 5.00 A. The rate at whichthe electric field between the plates ischanging is approximately

A. 5.65 1011 N m2/(C s)

B. 11.3 1011 N m2/(C s)

C. 2.45 1011 N m2/(C s)D. 12.4 1011 N m2/(C s)

E. 1.76 1011 N m2/(C s)


6/74

An ac voltage is applied across a capacitor.

Which figure best represents the magneticfield between the capacitor?


7/74

An ac voltage is applied across a capacitor.

Which figure best represents the magneticfield between the capacitor?


8/74

An ac voltage, V= 20 V sin (1000 rad/s t) isapplied across a capacitor of capacitance

C= 40 F. The capacitor is made of twocircular plate each of radius r= 5 cm. What isthe peak magnetic field at the circumference

of the capacitor?A. 1.2 T

B. 1.6.2 T

C. 3.2 T

D. 72 T

E. None of these is correct.


9/74

An ac voltage, V= 20 V sin (1000 rad/s t) isapplied across a capacitor of capacitance

C= 40 F. The capacitor is made of twocircular plate each of radius r= 5 cm. What isthe peak magnetic field at the circumference

of the capacitor?A. 1.2 T

B. 1.6.2 T

C. 3.2 TD. 72 T



10/74



Section 30-2: Maxwells Equations


11/74

Which of the following statements contradictsone of Maxwell's equations?

A. A changing magnetic field produces anelectric field.

B. The net magnetic flux through a closed

surface depends on the current inside.C. A changing electric field produces a

magnetic field.

D. The net electric flux through a closedsurface depends on the charge inside.

E. None of these statements contradict

any of Maxwell's equations.


12/74

Which of the following statements contradictsone of Maxwell's equations?

A. A changing magnetic field produces anelectric field.

B. The net magnetic flux through a closed

surface depends on the current inside.C. A changing electric field produces a

magnetic field.

D. The net electric flux through a closedsurface depends on the charge inside.

E. None of these statements contradict any of

Maxwell's equations.


13/74

If the existence of magnetic monopoles should ever

be confirmed, which of the following equations

would have to be altered?

apply.stillwouldAllE.

D.

C.

0B.

A.

c000

c

s

s0

inside

s

n

s

n

n

n

dAt

EIldB

dA

t

BldE

dAB

QdAE


14/74

If the existence of magnetic monopoles should ever

be confirmed, which of the following equations

would have to be altered?

apply.stillwouldAllE.

D.

C.

0B.

A.

c000

c

s

s0

inside

s

n

s

n

n

n

dAt

EIldB

dA

t

BldE

dAB

QdAE


15/74

Maxwell's equations

A. imply that the electric field due to a point

charge varies inversely as the square of thedistance from the charge.

B. describe how electric field lines diverge from apositive charge and converge on a negativecharge.

C. assert that the flux of the magnetic field vectoris zero through any closed surface.

D. describe the experimental observation thatmagnetic field lines do not diverge from anypoint space or converge to any point.

E. All of these are correct.


16/74

Maxwell's equations

A. imply that the electric field due to a point

charge varies inversely as the square of thedistance from the charge.

B. describe how electric field lines diverge from apositive charge and converge on a negativecharge.

C. assert that the flux of the magnetic field vectoris zero through any closed surface.

D. describe the experimental observation thatmagnetic field lines do not diverge from anypoint space or converge to any point.



17/74

Which of the following statements is false?

A. Isolated electric charges exist.B. Electric field lines diverge from positive

charges and converge on negative

charges.

C. The flux of the magnetic field vector iszero through any closed surface.

D. Isolated magnetic poles exist.

E. Changing electric fields induce

changing magnetic fields.


18/74

Which of the following statements is false?

A. Isolated electric charges exist.B. Electric field lines diverge from positive

charges and converge on negative

charges.

C. The flux of the magnetic field vector iszero through any closed surface.

D. Isolated magnetic poles exist.

E. Changing electric fields induce

changing magnetic fields.


19/74

Which of the following statements is true?

A. A changing electric field induces amagnetic field.

B. A changing magnetic field induces an

electric field.C. Maxwells equations predict the speed of

light.

D. Maxwells equations predict that light ismade up of oscillating electric andmagnetic waves.

E. All the above statements are true.


20/74


A. A changing electric field induces amagnetic field.

B. A changing magnetic field induces an

electric field.C. Maxwells equations predict the speed of

light.

D. Maxwells equations predict that light ismade up of oscillating electric andmagnetic waves.

E. All the above statements are true.


21/74



Section 30-3: The Wave Equation forElectromagnetic Waves


22/74


A. Both the Band the Ecomponents of an

electromagnetic wave satisfy the waveequation.

B. The phase of a wave traveling in the negative z

direction is kz+ wt.C. The speed of an electromagnetic wave traveling

in a vacuum is given by (0m0)1/2.

D. The magnitude of Ein an electromagnetic waveis greater than the Bmagnitude of by a factorof c.

E. All of these statements are true.


23/74


A. Both the Band the Ecomponents of an

electromagnetic wave satisfy the waveequation.

B. The phase of a wave traveling in the negative z

direction is kz+ wt.C. The speed of an electromagnetic wave traveling

in a vacuum is given by (0m0)1/2.

D. The magnitude of Ein an electromagnetic waveis greater than the Bmagnitude of by a factorof c.

E. All of these statements are true.


24/74

Which of the following functions satisfy theone-dimensional wave equation?

A. y(x, t) = y0 cos(kx wt)

B. y(x, t) = y0 sin(kx wt)

C. y(x, t) = y0 sin(kx wt) + Bcos(kx wt)

D. y(x, t) = y0 (sin kx) B(cos wt)

E. All of these functions satisfy the one-dimensional wave equation.


25/74

Which of the following functions satisfy theone-dimensional wave equation?

A. y(x, t) = y0 cos(kx wt)

B. y(x, t) = y0 sin(kx wt)

C. y(x, t) = y0 sin(kx wt) + Bcos(kx wt)

D. y(x, t) = y0 (sin kx) B(cos wt)

E. All of these functions satisfy theone- dimensional wave equation.


26/74


A. Maxwell's equations apply only to fields

that are constant in time.

B. Electromagnetic waves are longitudinalwaves.

C. The electric and magnetic fields are out ofphase in an electromagnetic wave.

D. The magnitude of Ein an electromagneticwave is greater than the Bmagnitude ofby a factor of c.

E. All of the above statements are true.


27/74


A. Maxwell's equations apply only to fields

that are constant in time.

B. Electromagnetic waves are longitudinalwaves.

C. The electric and magnetic fields are out ofphase in an electromagnetic wave.

D. The magnitude of Ein anelectromagnetic wave is greater thanthe Bmagnitude of by a factor of c.

E. All of the above statements are true.


28/74

)/(whereiswavefield

magneticingcorrespondThe.)(sin

bygivenisfieldelectricitsanddirection

in thegpropagatiniswaveneticelectromagAn

00

0

cEB

jtkxEE

i

.

)cos(E.

.sinD.

.

cosC.

.sinB.

.)sin(A.

0

0

0

0

0

ktkxBB

ktkxBB

jtkxBB

ktkxBB

itkxBB


29/74

)/(whereiswavefield

magneticingcorrespondThe.)(sin

bygivenisfieldelectricitsanddirection

in thegpropagatiniswaveneticelectromagAn

00

0

cEB

jtkxEE

i

.

)cos(E.

.sinD.

.

cosC.

.sinB.

.)sin(A.

0

0

0

0

0

ktkxBB

ktkxBB

jtkxBB

ktkxBB

itkxBB


30/74



Section 30-4: Electromagnetic Radiation


31/74

The visible portion of the electromagnetic

spectrum is closest to which of the followingintervals?

A. 200 to 500 nm

B. 300 to 600 nm

C. 400 to 700 nm

D. 500 to 800 nmE. 600 to 900 nm


32/74

The visible portion of the electromagnetic

spectrum is closest to which of the followingintervals?

A. 200 to 500 nm

B. 300 to 600 nm

C. 400 to 700 nm

D. 500 to 800 nmE. 600 to 900 nm


33/74

Electromagnetic waves that have a

wavelength of 300 m in free space have afrequency of

A. 1 103 Hz

B. 5 105 Hz

C. 1 106 Hz

D. 9 106 Hz

E. 1 1011 Hz


34/74

Electromagnetic waves that have a

wavelength of 300 m in free space have afrequency of

A. 1 103 Hz

B. 5 105 Hz

C. 1 106 Hz

D. 9 106 Hz

E. 1 1011 Hz


35/74

What is the frequency of 555-nm light?

A. 16.7 kHz

B. 5.40 1014 Hz

C. 5.40 1015 Hz

D. 1.70 107

HzE. 5.40 1017 Hz


36/74

What is the frequency of 555-nm light?

A. 16.7 kHz

B. 5.40 1014 Hz

C. 5.40 1015 Hz

D. 1.70 107

HzE. 5.40 1017 Hz


37/74

The wavelength of a 150-MHz television

signal is approximately

A. 1.0 m

B. 1.5 m

C. 2.0 m

D. 2.0 cm

E. 50 cm


38/74

The wavelength of a 150-MHz television

signal is approximately

A. 1.0 m

B. 1.5 m

C. 2.0 m

D. 2.0 cm

E. 50 cm


39/74

The wavelength of a 63.7-MHz

electromagnetic wave is approximately

A. 1.0 m

B. 4.7 m

C. 6.8 m

D. 7.2 cm

E. 50 cm


40/74

The wavelength of a 63.7-MHz

electromagnetic wave is approximately

A. 1.0 m

B. 4.7 m

C. 6.8 m

D. 7.2 cm

E. 50 cm


41/74

Light wave A has twice the frequency of light

wave B. The wavelength of light wave A is_____ that of light wave B.

A. equal to

B. twice

C. four times

D. halfE. one


42/74

Light wave A has twice the frequency of light

wave B. The wavelength of light wave A is_____ that of light wave B.

A. equal to

B. twice

C. four times

D. halfE. one


43/74

Arrange the following types ofelectromagnetic radiation in order of

increasing wavelength: gamma rays,infrared light, ultraviolet light, visible light.

A. Gamma rays are not electromagneticradiation.

B. gamma rays, infrared, visible, ultraviolet

C. gamma rays, ultraviolet, visible, infrared

D. visible, ultraviolet, infrared, gamma rays

E. ultraviolet, visible, infrared, gamma rays


44/74

Arrange the following types ofelectromagnetic radiation in order of

increasing wavelength: gamma rays,infrared light, ultraviolet light, visible light.

A. Gamma rays are not electromagneticradiation.

B. gamma rays, infrared, visible, ultraviolet

C. gamma rays, ultraviolet, visible, infrared

D. visible, ultraviolet, infrared, gamma rays

E. ultraviolet, visible, infrared, gamma rays


45/74

Of X rays, infrared radiation, and radio waves,which has the longest wavelength and which the

shortest?A. X rays have the longest, radio waves the shortest.

B. X rays have the longest, infrared radiation the

shortest.C. Radio waves have the longest, X rays the

shortest.

D. Radio waves have the longest, infrared radiationthe shortest.

E. Infrared radiation has the longest, X rays the

shortest.


46/74

Of X rays, infrared radiation, and radio waves,which has the longest wavelength and which the

shortest?A. X rays have the longest, radio waves the shortest.

B. X rays have the longest, infrared radiation the

shortest.C. Radio waves have the longest, X rays the

shortest.

D. Radio waves have the longest, infrared radiationthe shortest.

E. Infrared radiation has the longest, X rays the

shortest.


47/74

Which of the following groups is arranged in

order of increasing wavelength?

A. infrared, ultraviolet, microwaves

B. X rays, visible, infrared

C. gamma rays, ultraviolet, X rays

D. microwaves, gamma rays, visible

E. infrared, ultraviolet, gamma rays


48/74

Which of the following groups is arranged in

order of increasing wavelength?

A. infrared, ultraviolet, microwaves

B. X rays, visible, infrared

C. gamma rays, ultraviolet, X rays

D. microwaves, gamma rays, visible

E. infrared, ultraviolet, gamma rays

Th diff t i t th


49/74

There are many different regions to theelectromagnetic spectrum. These include,

(a) visible light, (b) gamma-rays, (c) infra-red,(d) micro-waves, (e) radio-waves, (f) ultra-violet, and (g) X-rays. Put them in order ofincreasing wavelength, starting with the

shortest wavelength first.A. bgdafge

B. bgfadce

C. bgafcde

D. bgfacde

E. bgafdce

Th diff t i t th


50/74

There are many different regions to theelectromagnetic spectrum. These include,

(a) visible light, (b) gamma-rays, (c) infra-red,(d) micro-waves, (e) radio-waves, (f) ultra-violet, and (g) X-rays. Put them in order ofincreasing wavelength, starting with the

shortest wavelength first.A. bgdafge

B. bgfadce

C. bgafcde

D. bgfacde

E. bgafdce

Whi h f th f ll i t t t b t li ht i


51/74

Which of the following statements about light ina vacuum is incorrect?

A. Light always travels with the same speed cregardless of the motion of the source orobserver.

B. Light has wavelike properties.

C. Light has particlelike properties.

D. Light is an electromagnetic wave with itselectric-field vector pointing parallel to thedirection of propagation.

E. Light can be plane polarized.

Whi h f th f ll i g t t m t b t light i


52/74

Which of the following statements about light ina vacuum is incorrect?

A. Light always travels with the same speed cregardless of the motion of the source orobserver.

B. Light has wavelike properties.

C. Light has particlelike properties.

D. Light is an electromagnetic wave withits electric-field vector pointing parallelto the direction of propagation.

E. Light can be plane polarized.


53/74

A beam of light is propagating in the xdirection. The electric-field vector

A. can oscillate in any arbitrary direction inspace.

B. must oscillate in the zdirection.

C. must oscillate in the yzplane.

D. must oscillate in the xdirection.E. must have a steady component in the x

direction.


54/74

A beam of light is propagating in the xdirection. The electric-field vector

A. can oscillate in any arbitrary direction inspace.

B. must oscillate in the zdirection.

C. must oscillate in the yzplane.

D. must oscillate in the xdirection.E. must have a steady component in the x

direction.

Th d t ti f di b


55/74

The detection of radio waves can beaccomplished with either a dipole antenna or

a loop antenna. The dipole antenna detectsthe _____ of the wave, and the loop antennadetects the _____ field of the wave.

A. electric field; electric

B. electric field; magnetic

C. magnetic field; magneticD. magnetic field; electric

E. electric and magnetic fields; electric

Th d t ti f di b


56/74

The detection of radio waves can beaccomplished with either a dipole antenna or

a loop antenna. The dipole antenna detectsthe _____ of the wave, and the loop antennadetects the _____ field of the wave.

A. electric field; electric

B. electric field; magnetic

C. magnetic field; magneticD. magnetic field; electric

E. electric and magnetic fields; electric


57/74

Which of the following does not result in theproduction of electromagnetic waves?

A. Charges moving at a constant velocity.

B. Charges that are accelerating or

decelerating.C. Charges moving around in a circle.

D. Electrons that make a transition from

one atomic level to another.

E. An oscillating electric current.


58/74

Which of the following does not result in theproduction of electromagnetic waves?

A. Charges moving at a constantvelocity.

B. Charges that are accelerating ordecelerating.

C. Charges moving around in a circle.

D. Electrons that make a transition fromone atomic level to another.

E. An oscillating electric current.


59/74

The nearest star to us, Alpha Centauri, is

4.30 light-years away. What is this distancein kilometers?

A. 4.1 1010 km

B. 4.1 1013 km

C. 4.1 1016 km

D. 6.8 1011

kmE. 6.8 1014 km


60/74

The nearest star to us, Alpha Centauri, is

4.30 light-years away. What is this distancein kilometers?

A. 4.1 1010 km

B. 4.1 1013 km

C. 4.1 1016 km

D. 6.8 1011

kmE. 6.8 1014 km

Y i t i ti f


61/74

You are using an antenna consisting of asingle loop of wire of radius 15.0 cm to

detect electromagnetic waves for whichErms = 0.200 V/m. If the wave frequency is600 Hz, the rms value of the emf induced inthe loop is approximately

A. 32.1 nV

B. 84.3 nV

C. 66.7 nV

D. 178 nV

E. 643 nV

Y i t i ti f


62/74

You are using an antenna consisting of asingle loop of wire of radius 15.0 cm to

detect electromagnetic waves for whichErms = 0.200 V/m. If the wave frequency is600 Hz, the rms value of the emf induced inthe loop is approximately

A. 32.1 nV

B. 84.3 nV

C. 66.7 nV

D. 178 nV

E. 643 nV

The left part of the figure shows a dipole oscillating in a


63/74

+

1 2 3 4

axis

sinusoidal function. Which of the curves best represents the

electric field along the axis of the dipole?

A. 1sinusoidal wave in the plane of the dipole.

B. 2sinusoidal wave perpendicular to the plane of the

dipole.

C. 3circular wave perpendicular to the plane of the

dipole.

D. 4circular wave in the plane of the dipole.




64/74

+

1 2 3 4

axis


electric field along the axis of the dipole?



dipole.


dipole.





65/74


magnetic field along the axis of the dipole centered about the

dipole?



dipole.


dipole.



+

1 2 3 4

axis



66/74


magnetic field along the axis of the dipole centered about the

dipole?



dipole.

C. 3

circular wave perpendicular to the plane of the

dipole.



+

1 2 3 4

axis

The Sun radiates about 3 83 1026 W of


67/74

The Sun radiates about 3.83 1026 W ofpower. How large should a perfectly

reflecting solar sail be on a space ship ofmass 50 kg to provide an acceleration of10-4 m/s2at the Earths orbit? The radius ofthe Earths orbit is 1.50 1011 m.

A. 550 m2

B. 625 m2

C. 1100 m2

D. 2500 m2


The Sun radiates about 3 83 1026 W of


68/74

The Sun radiates about 3.83 1026 W ofpower. How large should a perfectly

reflecting solar sail be on a space ship ofmass 50 kg to provide an acceleration of10-4 m/s2at the Earths orbit? The radius ofthe Earths orbit is 1.50 1011 m.

A. 550 m2

B. 625 m2

C. 1100 m2

D. 2500 m2



69/74

Electromagnetic waves are produced when

A. free electric charges accelerate.B. conduction electrons move with a

constant drift velocity in a conductor.

C. a conductor moves with constantvelocity through a magnetic field.

D. electrons bound to atoms and molecules

make transitions to higher energy states.



70/74

Electromagnetic waves are produced when

A. free electric charges accelerate.B. conduction electrons move with a

constant drift velocity in a conductor.

C. a conductor moves with constantvelocity through a magnetic field.

D. electrons bound to atoms and molecules

make transitions to higher energy states.



71/74

The polar plot of the intensityof electromagnetic radiation

from an electric-dipole antennashows that the intensity is

A. a maximum at = 0.

B. a minimum at = 90.

C. a maximum at = 90.

D. independent of the angle .



72/74

The polar plot of the intensityof electromagnetic radiation

from an electric-dipole antennashows that the intensity is

A. a maximum at = 0.

B. a minimum at = 90.

C. a maximum at = 90.

D. independent of the angle .


Th E h i b 28 000 li h f h


73/74

The Earth is about 28,000 light years from thecenter of the Milky Way Galaxy. If a supernova

explosion occurred approximately 14,000 lightyears away from us and released 2.0 1046 J ofenergy in a sudden burst of light, how muchenergy would enter one of your pupils? Assume

the diameter of a pupil to be about 4 mm.

A. 1.1 J

B. 3.0 1023 J

C. 3.5 J

D. 4.6 J

E. 2.2 J

Th E h i b 28 000 li h f h


74/74

The Earth is about 28,000 light years from thecenter of the Milky Way Galaxy. If a supernova

explosion occurred approximately 14,000 lightyears away from us and released 2.0 1046 J ofenergy in a sudden burst of light, how muchenergy would enter one of your pupils? Assume

the diameter of a pupil to be about 4 mm.

A. 1.1 J

B. 3.0 1023 J

C. 3.5 J

D. 4.6 J

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