Quiz 9: Magnetism and Electromagnetic Induction
Physics & Astronomy
Q 1Q 1
The rule for the interaction of magnetic poles is similar to the rule for electric
A)circuits.
B)polarization.
C)charges.
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C
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B
Q 3Q 3
Like kinds of magnetic poles repel while unlike kinds of magnetic poles
A)attract.
B)repel also.
C)may attract or repel.
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A
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Q 6Q 6
If you break a bar magnet in half you'll
A)destroy its magnetic properties.
B)have two magnets.
C)have four magnets.
D)none of the above
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Q 7Q 7
Magnet A has twice the magnetic field strength of magnet B and pulls on magnet B with a force of 100 N.The amount of force that magnet A exerts on magnet B is
A)about 50 N.
B)exactly 100 N.
C)more than 100 N.
D)not enough information
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Q 8Q 8
Compared with the huge force that attracts an iron tack to a strong magnet,the force that the tack exerts on the magnet is
A)relatively small.
B)equally huge.
C)not enough information
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Q 9Q 9
The ultimate source of all magnetism is
A)tiny bits of iron.
B)tiny domains of aligned atoms.
C)ferromagnetic materials.
D)moving electric charge.
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Q 10Q 10
A strong magnetic field easily penetrates
A)human flesh.
B)plastic coatings.
C)both of these
D)none of the above
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Q 11Q 11
Every spinning electron is
A)electrically charged.
B)a tiny magnet.
C)both of these
D)none of the above
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Q 12Q 12
Surrounding every stationary electron is
A)a magnetic field.
B)an electric field.
C)both of these
D)neither of these
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Q 13Q 13
Surrounding every moving electron is
A)a magnetic field.
B)an electric field.
C)both of these
D)neither of these
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Q 14Q 14
Magnetism is due to the motion of electrons as they
A)move around the nucleus.
B)spin on their axes.
C)both of these
D)neither of these
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Q 15Q 15
An iron rod becomes magnetic when
A)opposite ions accumulate at each end.
B)its atoms are aligned.
C)the net spins of many internal electrons are aligned.
D)its electrons stop moving and point in the same direction.
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Q 16Q 16
A compass needle in a magnetic field experiences
A)a torque.
B)a net force.
C)both of these
D)none of the above
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Q 17Q 17
Wood does not have magnetic properties because it contains no
A)iron or other metals.
B)magnetic domains.
C)moving electrons.
D)none of the above
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Q 18Q 18
Magnetic domains normally occur in
A)iron.
B)copper.
C)silver.
D)all of the above
E)none of the above
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Q 19Q 19
A magnet will become weaker if it is
A)dropped on a hard surface.
B)held in a hot flame.
C)either
D)neither
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Q 20Q 20
An iron nail is attracted
A)more strongly to the north pole of a magnet.
B)more strongly to the south pole of a magnet.
C)equally to either pole of a magnet.
D)none of the above
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Q 21Q 21
A bar magnet that holds a chain of nails illustrates
A)magnetic field displacement.
B)magnetic induction.
C)electromagnetic induction.
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Q 22Q 22
Several paper clips dangle from the north pole of a magnet.The induced pole in the bottom of the lowermost paper clip is a
A)north pole.
B)south pole.
C)either of these
D)neither of these
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Q 23Q 23
When a bar magnet is broken in half,the strength of the four new poles relative to pole strength before breaking is
A)less than half.
B)half.
C)the same.
D)somewhat more.
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Q 24Q 24
The magnetic field lines generated by a bar magnet
A)are external only.
B)are both external and internal to the magnet.
C)follow an inverse-square law.
D)none of the above
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Q 25Q 25
The magnetic field lines about a straight current-carrying wire are
A)circular.
B)radial.
C)elliptical.
D)spiral.
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Q 26Q 26
Magnetic field lines about a current-carrying wire
A)extend radially from the wire.
B)circle the wire in closed loops.
C)both of these
D)none of the above
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Q 27Q 27
When current reverses direction in a wire,the surrounding magnetic field
A)also reverses direction.
B)becomes momentarily stronger.
C)contracts.
D)expands.
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Q 28Q 28
When a current-carrying wire is bent into a loop,its magnetic field inside the loop
A)weakens.
B)becomes concentrated.
C)cancels.
D)none of the above
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Q 29Q 29
As the number of loops in a current-carrying wire coil is increased,the magnetic field becomes
A)more spread out.
B)more stable.
C)stronger.
D)weaker.
E)none of the above
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Q 30Q 30
The magnetic field strength inside a current-carrying coil will be greater if the coil encloses
A)a vacuum.
B)a wooden rod.
C)a glass rod.
D)an iron rod.
E)none of the above
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Q 31Q 31
A magnetic field exists in a current-carrying coil of wire
A)if it contains a piece of iron.
B)with or without a contained piece of iron.
C)only if the current changes.
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Q 32Q 32
The magnetic field inside a current-carrying coil increases when
A)current is increased.
B)the number of loops of wire in the coil increases.
C)an iron core is inserted.
D)all of the above
E)none of the above
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Q 33Q 33
A common electromagnet consists of a
A)bar magnet that carries an electric current.
B)current-carrying wire coil.
C)current-carrying coil with a piece of iron inside.
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Q 34Q 34
Superconducting electromagnets
A)account for cases of magnetic levitation.
B)are characterized by easy penetration of external magnetic fields.
C)both of these
D)none of the above
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Q 35Q 35
A superconducting electromagnet makes use of
A)zero resistance coils of wire.
B)super-high temperatures.
C)high-speed electrons.
D)close packing of high-density magnetic domains.
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Q 36Q 36
The lift experienced by Maglev trains is due to magnetic
A)attraction.
B)repulsion.
C)dipoles.
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Q 37Q 37
Moving electric charges will interact with
A)an electric field.
B)a magnetic field.
C)both of these
D)none of the above
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Q 38Q 38
Into which stable force field can a proton be placed at rest without being accelerated?
A)magnetic field
B)electric field
C)both of these
D)none of the above
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Q 39Q 39
Maximum magnetic force occurs when electrons move
A)in the same direction as the magnetic field.
B)opposite to the magnetic field direction.
C)perpendicular to the magnetic field direction.
D)at non-right angles to the magnetic field direction.
E)none of the above
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Q 40Q 40
The minimum or no magnetic force on a moving electron occurs for motion
A)parallel to the magnetic field.
B)perpendicular to the magnetic field.
C)at non-right angles to the magnetic field direction.
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Q 41Q 41
No magnetic force acts on a current carrying wire when it
A)carries a very small current.
B)is perpendicular to the magnetic field.
C)either or both of these
D)none of the above
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Q 42Q 42
A magnetic force acts most strongly on a current carrying wire when it
A)carries a very large current.
B)is perpendicular to the magnetic field.
C)either or both of these
D)none of the above
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Q 43Q 43
When an electron passes through the magnetic field of a horseshoe magnet,the electron's
A)speed is increased.
B)direction of motion is changed.
C)both of these
D)none of the above
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Q 44Q 44
An electron beam directed through a magnetic field
A)may be deflected.
B)may experience a force.
C)both of these
D)neither of these
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Q 45Q 45
No net force acts on a loop of wire in a magnetic field when
A)no current is in the loop.
B)no magnetic field lines pass through the loop.
C)both of these
D)neither of these
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Q 46Q 46
If a magnet produces a force on a current-carrying wire,the wire
A)produces a force on the magnet.
B)may or may not produce a force on the magnet.
C)neither of these
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Q 47Q 47
Near our planet Earth are
A)cosmic rays.
B)magnetic fields.
C)both of these
D)none of the above
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Q 48Q 48
Earth's magnetic field affects cosmic rays by
A)deflecting them.
B)slowing their speeds.
C)destroying them.
D)absorbing them.
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Q 49Q 49
The intensity of cosmic rays bombarding the Earth's surface is greatest at
A)the poles.
B)mid-latitudes.
C)the equator.
D)no particular locations.
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Q 50Q 50
A galvanometer measures
A)magnetic fields.
B)electric current.
C)electric voltage.
D)none of the above
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Q 51Q 51
A galvanometer is a useful device in electric
A)electromagnets.
B)transformers.
C)generators and motors.
D)meters.
E)none of the above
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Q 52Q 52
A galvanometer calibrated to read current is
A)an ammeter.
B)a voltmeter.
C)an ohm meter.
D)none of the above
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Q 53Q 53
A galvanometer calibrated to read potential difference is
A)an ammeter.
B)a voltmeter.
C)an ohm meter.
D)none of the above
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Q 54Q 54
Since magnetic force on a moving electron is always perpendicular to its direction of motion,magnetic force is unable to change an electron's
A)speed.
B)direction.
C)speed and direction.
D)none of the above
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Q 55Q 55
Which force field can increase a moving electron's speed?
A)electric field
B)magnetic field
C)both of these
D)none of the above
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Q 56Q 56
Which force field can both accelerate an electron and change its speed?
A)electric field.
B)magnetic field.
C)both of these
D)none of the above
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Q 57Q 57
Which of these singly ionized atoms of the same speed will curve most in a magnetic field?
A)helium
B)iron
C)uranium
D)all the same
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Q 58Q 58
In which of these locations is cosmic ray intensity greatest?
A)Mexico City
B)Toronto
C)Singapore
D)all about the same
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Q 59Q 59
The discovery of electromagnetic induction is credited to
A)Joseph Henry in America.
B)Michael Faraday in England.
C)both of these
D)none of the above
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Q 60Q 60
Faraday's law describes
A)electromagnetic induction.
B)the connection between current,voltage,and resistance.
C)the attraction and repulsion of magnetic poles.
D)the force between magnetic poles.
E)all of the above
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Q 61Q 61
Electromagnetic induction is employed in
A)credit card readers.
B)computers.
C)mobile phones.
D)all of the above
E)none of the above
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Q 62Q 62
Electromagnetic induction occurs in a coil when there is a change in
A)electric field intensity.
B)magnetic field intensity.
C)voltage.
D)the coil's polarity.
E)none of the above
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Q 63Q 63
Voltage can be induced in a wire by
A)moving the wire near a magnet.
B)moving a magnet near the wire.
C)changing the current in a nearby wire.
D)all of the above
E)none of the above
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Q 64Q 64
When a change of magnetic field occurs in a closed loop of wire,
A)a voltage is induced in the wire.
B)current is made to flow in the loop of wire.
C)electromagnetic induction occurs.
D)all of the above
E)none of the above
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Q 65Q 65
Changing the magnetic field intensity in a copper coil induces
A)current.
B)voltage.
C)both of these
D)none of the above
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Q 66Q 66
Thrust a magnet into a coil of wire and you'll induce
A)voltage.
B)current.
C)both of these
D)none of the above
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Q 67Q 67
When a bar magnet is thrust into a coil of wire,a greater voltage is induced with
A)a greater number of loops in the coil.
B)faster thrusting motion.
C)a stronger bar magnet.
D)all of the above
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Q 68Q 68
When a bar magnet is thrust at the same speed into a coil having twice the number of loops,the induced voltage is
A)half.
B)the same,no different.
C)twice as much.
D)four times as much.
E)none of the above
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Q 69Q 69
The frequency with which a magnet plunges into and out of a wire coil equals the frequency of the induced
A)voltage.
B)current.
C)both of these
D)none of the above
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Q 70Q 70
When a bar magnet is thrust into a coil of wire,the coil
A)attracts the magnet as it enters.
B)repels the magnet as it enters.
C)both of these
D)none of the above
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Q 71Q 71
A copper ring can be made to levitate about the extended bar of an electromagnet because the magnetic field induced in the ring
A)remains strong and steady.
B)opposes the field producing it.
C)is attracted to the top end of the bar.
D)none of the above
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Q 72Q 72
The amount of current produced by electromagnetic induction depends on the
A)amount of induced voltage.
B)resistance of the circuit to which it is connected.
C)both of these
D)none of the above
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Q 73Q 73
The metal detectors that travelers walk through at airports operate via
A)Ohm's law.
B)Faraday's law.
C)Coulomb's law.
D)Newton's laws.
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Q 74Q 74
Metal detectors that locate metal beneath sand on a beach are activated by
A)electric fields.
B)magnetic fields.
C)electromagnetic induction.
D)alternating current.
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Q 75Q 75
Fred swings a sheet of copper in pendulum fashion between the poles of a strong magnet.The sheet slows in entering the magnetic field because the field
A)induces swirling currents in the copper and accompanying magnetic fields that resist motion.
B)experiences both air and magnetic friction.
C)is repelled by free electrons in the copper.
D)none of the above
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Q 76Q 76
If you drop a bar magnet in a vertical copper pipe it will fall slowly because
A)of air resistance.
B)it induces a magnetic field in the pipe that resists motion of the magnet.
C)the copper is a good conductor of both electricity and magnetism.
D)of electron repulsion.
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Q 77Q 77
Alternating current is normally produced by a
A)battery.
B)generator.
C)both of these
D)none of the above
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Q 79Q 79
Which of these statements is true?
A)a battery produces dc and a generator produces ac
B)a battery produces ac and a generator produces dc
C)a battery and a generator produce dc
D)a battery and a generator produce ac
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Q 80Q 80
Compared with a motor,a generator is
A)one and the same.
B)its opposite.
C)of an entirely different design.
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Q 81Q 81
An electric motor and electric generator are
A)very similar devices.
B)entirely different devices.
C)none of the above
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Q 82Q 82
An electric motor and electric generator differ in
A)the roles of input and output.
B)basic construction.
C)size.
D)quality.
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Q 83Q 83
A device that transforms electrical energy to mechanical energy is a
A)generator.
B)motor.
C)transformer.
D)magnet.
E)none of the above
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Q 84Q 84
A device that transforms mechanical energy to electrical energy is a
A)generator.
B)motor.
C)transformer.
D)magnet.
E)none of the above
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Q 85Q 85
Voltage produced by a generator alternates because
A)it produces pulses of current.
B)the magnetic field that produces it alternates.
C)alternations in the mechanical energy input.
D)effectively it is an ac motor in reverse.
E)the current it produces alternates.
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Q 86Q 86
A turbogenerator produces
A)energy.
B)power.
C)neither,but transforms energy from one form to another.
D)none of the above
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Q 87Q 87
Disregarding the effects of friction,a cyclist will coast farther when a lamp powered by a wheel generator is
A)of low wattage.
B)of high wattage.
C)burned out.
D)none of the above
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Q 88Q 88
Power is the rate at which
A)energy is transferred.
B)voltage can be changed.
C)current can be induced.
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Q 89Q 89
The rate at which energy is transferred is
A)power.
B)electromagnetic induction.
C)transformation.
D)none of the above
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Q 90Q 90
An electric generator
A)can create enough energy to light cities.
B)can convert mechanical energy to electric energy.
C)needs no energy source.
D)all the above
E)none of the above
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Q 91Q 91
The sloshing of electrons inside a generator needs
A)an outside source of energy.
B)a copper lattice.
C)positive ions.
D)none of the above
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Q 92Q 92
The energy source for a generator may be
A)a waterfall.
B)steam from a turbine.
C)wind.
D)any of these
E)none of the above
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Q 93Q 93
A topic that most underlies electrical studies and all of physics is
A)Newton's laws of motion.
B)the conservation of momentum.
C)the conservation of energy.
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Q 94Q 94
The rate at which a transformer transfers energy is called
A)electromagnetic induction.
B)transformer efficiency.
C)power.
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Q 95Q 95
A transformer requires
A)alternating voltage.
B)direct current.
C)both of these
D)none of the above
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Q 96Q 96
A transformer actually transforms
A)energy from one value of voltage to another.
B)magnetic and electric field lines.
C)generators into motors.
D)motors into generators.
E)all of the above
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Q 97Q 97
Compared with the power input to an ideal transformer,the power output is
A)greater.
B)less.
C)either greater or less.
D)the same.
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Q 98Q 98
Compared with the voltage input to a transformer,the voltage output can be
A)greater.
B)less.
C)greater or less.
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Q 99Q 99
Transformers use ac so there will be the required
A)transfer of energy from coil to coil.
B)voltage for transformation.
C)change in magnetic field for operation.
D)change in input current.
E)magnetic field intensities.
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Q 100Q 100
An efficient step-up transformer increases
A)power.
B)energy.
C)both of these
D)none of the above
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Q 101Q 101
An efficient step-down transformer decreases
A)current.
B)voltage.
C)power.
D)energy.
E)all of the above
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Q 102Q 102
The principal difference between a step-up and step-down transformer is
A)step-up transformers can handle more current.
B)different geometries.
C)different ratios of turns for each set of loops or coils.
D)none of the above
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Q 103Q 103
Compared with the current in the primary coil of a transformer,the current in the secondary coil
A)is greater.
B)is less.
C)can be greater or less.
D)none of the above
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Q 104Q 104
The voltage across the input terminals of a transformer is 110 V.The primary coil has 50 loops and the secondary has 25 loops.The output is
A)25 V.
B)55 V.
C)110 V.
D)220 V.
E)none of the above
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Q 105Q 105
The voltage across the input terminals of a transformer is 110 V.The primary coil has 50 loops and the secondary coil has 100 loops.The output is
A)25 V.
B)55 V.
C)110 V.
D)220 V.
E)none of the above
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Q 106Q 106
A certain transformer doubles input voltage.If the primary coil has 10 A of current,then the current in the secondary coil is
A)2 A.
B)5 A.
C)10 A.
D)25 A.
E)none of the above
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Q 107Q 107
An ideal transformer has 50 turns in its primary and 250 turns in its secondary.When 12-V ac is connected to the primary,the voltage available to the secondary is
A)5 V.
B)10 V.
C)30 V.
D)60 V.
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Q 108Q 108
An ideal transformer has 50 turns in the primary and 500 turns in the secondary.An input of 12 V will produce an output of
A)12 V.
B)120 V.
C)1200 V.
D)none of the above
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Q 109Q 109
If the primary of a transformer were connected to a dc power source,the transformer would have a voltage output
A)at a higher efficiency than with an ac source.
B)the same as its input.
C)that is also dc.
D)only briefly while being connected or disconnected.
E)none of the above
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Q 110Q 110
A current of 4 A exist in the primary coil of a transformer powered with 110 V.What is the power output of the secondary coil?
A)27.5 W
B)110 W
C)440 W
D)880 W
E)not enough information
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Q 111Q 111
A transformer for a laptop computer converts a 120-V input to a 24-V output.Compared with the number of turns on the primary coil,the secondary has
A)1/5 as many turns.
B)5 times as many turns.
C)the same number of turns.
D)none of the above
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Q 112Q 112
An electronic game requires 6 V for operation.With a transformer it can be powered by a 120-V outlet.If the primary has 500 turns,the secondary has
A)4 turns.
B)25 turns.
C)50 turns.
D)more than 50 turns.
E)none of the above
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Q 113Q 113
A transformer has an input of 6 V and an output of 42 V.If the input is changed to 12 V,the output would be
A)12 V.
B)48 V.
C)84 V.
D)more than 84 V.
E)none of the above
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Q 114Q 114
The rapid change of a magnetic field induces
A)an electric field.
B)a stronger magnetic field.
C)both of these
D)none of the above
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Q 115Q 115
The rapid change of an electric field induces
A)a stronger electric field.
B)a magnetic field.
C)both of these
D)none of the above
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Q 116Q 116
Maxwell's counterpart to Faraday's law simply states that
A)each change in one field induces the other.
B)electric and magnetic fields are one and the same.
C)induced fields are parallel to each other.
D)all of the above
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Q 117Q 117
In the field induction credited to Maxwell,wires
A)can be insulated or non-insulated.
B)are minimized.
C)are not needed.
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Q 118Q 118
The induced electric and magnetic fields of Maxwell are
A)parallel to each other.
B)perpendicular to each other.
C)non-directional.
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Q 119Q 119
Induced electric and magnetic fields produce
A)stronger electric or magnetic field.
B)higher voltages produced by Faraday induction.
C)both of these
D)none of the above
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Q 120Q 120
Electric and magnetic fields combine to produce
A)sound.
B)light.
C)both of these
D)none of the above
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Q 121Q 121
The frequency of a generated electromagnetic wave matches the
A)field strength of the fields.
B)energy of the fields.
C)frequency of vibrating charges that produced it.
D)frequency of domains in the magnetic part of the wave.
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Q 122Q 122
What any type of field generation cannot create is
A)light.
B)electromagnetic waves.
C)energy.
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Q 123Q 123
A friend says that changing electric and magnetic fields underlie the production of light.
A)agree with your friend
B)disagree with your friend
C)find a new friend
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Q 124Q 124
What is the cause of a magnetic field about a permanent magnet and about a current-carrying wire?
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Q 126Q 126
What happens to a current-carrying wire in a magnetic field? How does orientation of the wire make a difference?
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Q 129Q 129
What correction do you suggest to a friend who states that a step-up transformer boosts energy,while a step-down transformer reduces energy in a circuit?
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