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WorksheetsHewitt Ch 22-24 hw review
Total questions: 120
Worksheet time: 3600secs
Name
Class
Date
1.
Why does the gravitational force between Earth and Moon predominate over electrical forces?
a)
The electric force between Earth and Moon cancels out because they have an equal number of positive and negative charges.
b)
The electrical force gets smaller more quickly with distance than the inverse square gravitational force.
c)
Gravitational forces grow exponentially with the number of particles, while electrical forces simply add.
d)
The gravitational force between two protons is billions of times stronger than the electrical force.
2.
Which part of an atom is positively charged, and which part is negatively charged?
a)
The nucleus is positively charged and the electron cloud is negatively charged.
b)
Atoms are made entirely of neutral particles.
c)
The nucleus is negatively charged and the electron cloud is positively charged.
d)
The core is positively charged, the mesosphere is neutrally charged, and the exosphere is negatively charged.
3.
How does the charge of one electron compare to that of another electron? How does it compare with the charge of a proton? How do the masses of protons and electrons compare?
a)
All electrons have the same charge. Electron charge is equal and opposite to the proton charge. A electron has 1800 times the mass of a proton.
b)
All electrons and protons have exactly the same charge. A proton has 1800 times the mass of an electron.
c)
All electrons and protons have exactly the same charge and mass.
d)
All electrons have the same charge. Electron charge is equal and opposite to the proton charge. A proton has 1800 times the mass of an electron.
4.
What is the most common net charge of an atom?
a)
Negative
b)
Positive
c)
Dipole
d)
Neutral
5.
Most atoms normally have a net charge that is
a)
positive in the nucleus and slightly more negative in its electrons
b)
positive
c)
negative
d)
zero
6.
What is a positive ion? What is a negative ion?
a)
A positive ion is a neutral atom that has lost one or more protons. A negative ion is a neutral atom that has gained one or more protons.
b)
A positive ion is a neutral atom that has gained one or more electrons. A negative ion is a neutral atom that has lost one or more electrons.
c)
A positive ion is a neutral atom that has lost one or more electrons. A negative ion is a neutral atom that has gained one or more electrons.
d)
A positive ion is a neutral atom that has lost one or more neutrons. A negative ion is a neutral atom that has gained one or more neutrons.
7.
When we say charge is conserved, we mainly mean that charge can be
a)
created and destroyed in equal amounts
b)
saved, like money in a bank
c)
constant in all bodies
d)
transferred without loss like money in a bank
8.
How does one coulomb of charge compare with the charge of a single electron?
a)
A coulomb of charge is the charge associated with 1.6 × 10^(-19) electrons.
b)
A coulomb of charge is the charge associated with 6.25 × 10^18 electrons.
c)
A coulomb of charge is the charge associated with 1.6 × 10^19 electrons.
d)
A coulomb of charge is the charge associated with half the charge of 6.25 × 10^(-18) electrons.
9.
How is Coulomb's law similar to Newton's law of gravitation? How is it different?
a)
Newton's law of gravitation is attractive, whereas Coulomb's law is attractive or repulsive. Both are proportional to the inverse square of distance.
b)
Coulomb's law can be attractive or repulsive but is inversely proportional to distance.
c)
Newton's law of gravitation is attractive, whereas Coulomb's law is always repulsive. Both are inverse square.
d)
Newton's law of gravitation is attractive or repulsive, whereas Coulomb's law is attractive only. Both are inverse square.
10.
What is meant by conservation of charge?
a)
All electrons have the same electric charge.
b)
Whenever an electron is created, an equal and oppositely charged proton is also created.
c)
Net charge cannot be created or destroyed.
d)
The amount of charge in every nucleus is the same.
11.
What is meant by saying that charge is quantized?
a)
All charged objects have a charge that is an integer multiple of the charge of an electron.
b)
All objects have a charge that is equal to the charge of the electron.
c)
All electric charges are fractions of the electron charge with a 1 in the numerator.
d)
All electric charge is measured in units called "quants."
12.
Which particle has exactly one quantum unit of charge?
a)
Proton
b)
Quark
c)
Neutron
d)
Alpha particle
13.
Coulomb's law is most similar to which of these laws?
a)
Archimedes' laws of hydrostatics
b)
Newton's law of gravity
c)
The law of electric potential
d)
The conservation of energy
14.
Why are metals good conductors of both heat and electricity?
a)
The outer shell electrons in metals are free to move from atom to atom.
b)
The outer shell electrons in atoms vibrate in place and emit electromagnetic radiation that travels throughout the metal.
c)
The outer shell electrons in metals move with zero resistance, making all metals superconductors.
d)
The outer shell electrons in metals are tightly bound, making it easy for vibrations to move from one atom to the next.
15.
Why are materials such as glass and rubber good insulators?
a)
Electrons are loosely bound to their atoms, making them good conductors of heat.
b)
Electrons are loosely bound to their atoms, making them poor conductors of heat.
c)
Electrons are tightly bound to their atoms, making them poor conductors of heat.
d)
Electrons are tightly bound to their atoms, making them good conductors of heat.
16.
How does a semiconductor differ from a conductor or an insulator?
a)
A semiconductor has exactly half the resistance of a conductor and twice the resistance of an insulator.
b)
A semiconductor has exactly half the resistance of an insulator and twice the resistance of a conductor.
c)
A semiconductor is a good conductor of electric current but a poor conductor of heat.
d)
A semiconductor is neither a good conductor nor a good insulator - it has a middle range of resistivity.
17.
What happens to electrons in any charging process?
a)
Electrons transfer from one place to another.
b)
Electrons stay in place as protons are transferred from one place to another.
c)
Electrons are destroyed.
d)
Electrons are created.
18.
What kind of charging occurs when you slide your body across a plastic surface?
a)
Charging by friction occurs. Electrons move from a neutral object to a negatively charged object.
b)
Charging by friction occurs. Electrons are transferred when one object rubs against another.
c)
Charging by induction occurs. Electrons in one object push away electrons in the other object.
d)
Charging by touching occurs. Electrons move from a negatively charged object to a neutral object.
19.
A glass marble is rubbed against a piece of silk. As a result the piece of fabric acquires extra electrons. What happens to the glass marble?
a)
The marble has lost the same number of electrons acquired by the piece of silk.
b)
The marble has acquired the same number of electrons acquired by the piece of silk.
c)
The marble acquires a positive charge and repels the piece of silk.
d)
The marble acquires a positive charge and attracts the piece of silk.
e)
More than one answer is correct
20.
Consider the situation in the figure below, where two charged rods are placed a distance d on either side of an aluminum can. What does the can do?
a)
Rolls to the left
b)
Rolls to the right
c)
Stays still
21.
A positive charge is kept (fixed) at the center inside a fixed spherical neutral conducting shell. The large positive charge inside the shell causes equal in magnitude charges distributed on the inner and outer surfaces of the spherical shell. Which of the pictures best represents the charge distribution on the inner and outer walls of the shell?
a)
1
b)
2
c)
3
d)
4
e)
5
22.
Which molecule is an example of a common electric dipole?
a)
An oxygen molecule
b)
A carbon dioxide molecule
c)
A nitrogen molecule
d)
A water molecule
23.
In terms of net charge, how does an electrically polarized object differ from an electrically charged object?
a)
An electrically polarized object must have a positive net charge, while a charged object must have either a positive or a negative net charge.
b)
An electrically polarized object must have a positive or a negative net charge, while a charged object must have a positive net charge.
c)
An electrically polarized object must have a negative net charge, while a charged object must have either a positive or a negative net charge.
d)
An electrically polarized object can have zero net charge, while a charged object cannot have zero net charge.
24.
Give two examples of common force fields and name the sources of these fields.
a)
Gravity fields made by dipoles, electric fields made by charge
b)
Gravity fields made by mass, electric fields made by charge
c)
Gravity fields made by charge, electric fields made by mass
d)
Gravity fields made by mass, magnetic fields made by static charge
25.
How is the direction of an electric field defined?
a)
A field is not a vector, so it does not have a direction.
b)
The direction of the field is the direction of the force on a neutron.
c)
The direction of the field is the direction of the force on an electron.
d)
The direction of the field is the direction of the force on a positive test charge.
26.
Why is there no electric field at the center of a charged spherical metal ball?
a)
There are an equal number of electrons and protons, so the field everywhere is zero.
b)
Because of mutual attraction, mobile protons in the conductor will spread out uniformly over the outer surface of the ball, so the force and the field on a test charge at the center is zero.
c)
Because of mutual repulsion, mobile electrons in the conductor will spread out uniformly over the outer surface of the ball, so the force and the field on a test charge at the center is zero because opposing forces balance in every direction.
d)
There are an equal number of electrons and positrons, so the field everywhere is zero.
27.
The net charge on a polarized molecule is normally
a)
zero
b)
the same as the charge that produces the polarization
c)
re-oriented
d)
opposite to the charge that produces the polarization
28.
An electric field is basically
a)
a source of voltage
b)
the same as a gravitational field
c)
a vector quantity
d)
an invisible force
29.
Electric potential, unlike electric potential energy, is measured in units o
a)
coulombs
b)
volts
c)
joules
d)
conduction
30.
A highly-charged party balloon is not dangerous when it
a)
contains equal numbers of positive and negative charges
b)
has an insulating rather than a conducting surface
c)
is electrically grounded
d)
contains little overall energy
31.
The net charge on an energized capacitor is normally
a)
either positive or negative
b)
zero
c)
positive
d)
negative
32.
The electric field inside the dome of a highly-charged Van de Graaff generator is
a)
the inverse of the field close to its outer surface
b)
at a potential that depends on the amount of surface charge
c)
zero
d)
a source of energy
33.
How much energy is given to each coulomb of charge that flows through a 1.5-V battery?
a)
1.5 watts
b)
0.66 joules
c)
1.5 joules
d)
1.5 watts
34.
A balloon may easily be charged to several thousand volts. Does that mean it has several thousand joules of energy? Explain.
a)
No. Energy is voltage times charge, so you need a coulomb of charge to get several thousand joules of energy.
b)
Yes. Several thousand volts are identical to several thousand joules.
c)
No. It has several million joules of energy.
d)
Yes. Charge rearranges itself on the balloon until the energy is several thousand joules.
35.
Where is the energy stored in a capacitor?
a)
The energy is stored in the electric field inside the metal of both the positive and the negative plates.
b)
The energy is stored in the electric field between the plates.
c)
The energy is stored in the electric field inside the metal of the positive plate.
d)
The energy is stored in the battery connected to the plates.
36.
A flow of electric charge in a wire normally requires a
a)
sustained energy difference across the ends of the wire
b)
pump
c)
voltage source
d)
potential difference across the ends of the wire
37.
What condition is necessary for the sustained flow of water in a pipe? What analogous condition is necessary for the sustained flow of charge in a wire?
a)
In both cases, an electrical potential difference, often provided by a battery, is needed for both water and electricity to flow continuously.
b)
A difference in water density is needed for water to flow in a pipe. A difference in charge density is needed for charge to flow in a wire.
c)
A continuous pressure difference, often provided by a pump, is needed for water to flow. A continuous potential difference, often provided by a battery, is needed for charge to flow.
d)
A continuous pressure difference, often provided by a pump, is needed for water to flow. There is no analogous condition for charge to flow in a wire.
38.
Why are electrons, rather than protons, the principal charge carriers in metal wires?
a)
Electrons are lighter, so they move faster than protons with the same kinetic energy.
b)
Protons are free to move through the metal, whereas electrons are fixed in place.
c)
Electrons are in the nucleus, whereas protons are in a cloud around the nucleus.
d)
Electrons are free to move through the metal, whereas protons are fixed in place.
39.
What exactly is an ampere?
a)
The flow of one ohm per second
b)
The flow of one joule per second
c)
The force between two wires carrying electric current
d)
The flow of one coulomb per second
40.
An electric current of 5 amperes in a wire carries
a)
5 coulombs per second
b)
5 joules per coulomb
c)
5 coulombs per joule
d)
5 joules per ohm
e)
5 volts per coulomb
41.
Name two kinds of practical "electric pumps."
a)
Electric motors and a batteries
b)
Batteries and automobile alternators
c)
Linear accelerators and Van de Graaf generators
d)
Batteries and Van de Graaf generators
42.
How much energy is supplied to each coulomb of charge that flows through a 12-V battery?
a)
120 joules
b)
12 watts
c)
120 watts
d)
12 joules
43.
Does electric charge flow across a circuit or through a circuit? Does voltage flow across a circuit or is it impressed across a circuit?
a)
Charge flows through and voltage is impressed across a circuit.
b)
Charge flows through and voltage flows across a circuit.
c)
Charge and voltage both flow across a circuit.
d)
Charge flows across and voltage is impressed across a circuit.
44.
A voltage source in a circuit provides electrical
a)
resistance
b)
pressure
c)
grounding
d)
force
45.
Will water flow more easily through a wide pipe or a narrow pipe? Will current flow more easily through a thick wire or a thin wire?
a)
Narrow pipe and thin wire
b)
Wide pipe and narrow wire
c)
Wide pipe and thick wire
d)
Narrow pipe and thick wire
46.
Does heating a metal wire increase or decrease its electrical resistance? Why?
a)
It decreases resistance because a metal becomes a superconductor when warmed.
b)
It decreases resistance because higher temperatures free more electrons to carry current.
c)
It decreases resistance because atoms at higher temperatures jostle into the way of moving electrons.
d)
It increases resistance because atoms at higher temperatures jostle into the way of moving electrons.
47.
What is the unit of electrical resistance?
a)
Amp per volt
b)
Amp
c)
Ohm
d)
Volt
48.
The electric resistance in a length of wire is doubled when the wire is
a)
doubled in temperature
b)
half as long
c)
properly insulated
d)
twice as long
49.
If the voltage impressed across a circuit is held constant while the resistance doubles, what change occurs in the current?
a)
It is cut in half.
b)
It stays the same.
c)
It doubles.
d)
It is cut to one quarter of its original value.
50.
If the resistance of a circuit remains constant while the voltage across the circuit decreases to half its former value, what change occurs in the current?
a)
It doubles.
b)
It quadruples.
c)
It is cut in half.
d)
It stays the same.
51.
How does wetness affect the resistance of your body?
a)
Wet bodies have lower resistance.
b)
Wet bodies have higher resistance.
c)
Wet bodies have the same resistance as dry bodies.
d)
Wet bodies have no resistance.
52.
What is the function of the round third prong in a modern household electric plug?
a)
It supplies a backup source of voltage.
b)
It grounds the case to zero potential.
c)
It provides safety against lightning strikes.
d)
It attaches the case to 120 volts potential.
53.
What is the relationship between current, resistance, and voltage difference?
a)
Current = Voltage Difference / Resistance
b)
Current = Resistance / Voltage Difference
c)
Current = Voltage Difference x Resistance
54.
How does the current change if you increase the resistance, keeping the voltage difference the same?
a)
The current stays the same.
b)
The current decreases.
c)
The current increases.
55.
What factors does the resistance offered by a piece of conductor depend upon?
a)
material of the conductor
b)
both the geometry and the material of the conductor
c)
neither the geometry nor the material of the conductor
d)
only the geometry of the conductor
56.
How does the resistance of a thick piece of copper wire compare to the resistance of a thin piece of copper wire?
a)
The resistance of the thick piece is greater than that of the thin piece.
b)
The resistance of the thin piece is greater than that of the thick piece.
c)
Both the wire and narrow piece of copper provide the same resistance.
57.
What is the current in a bulb if the resistance of its filament is 2 ohms and it is connected across a 6-volt battery?
a)
12 amps
b)
3 amps
c)
0.33 amps
58.
When your body undergoes electric shock, the source of moving electrons is
a)
moisture between you and a voltage source
b)
the object making electrical contact
c)
electrons already in your body
d)
mainly from the ground
59.
Does a battery produce dc or ac? Does the generator at a commercial power station produce dc or ac?
a)
Both are dc.
b)
Both are ac.
c)
The battery is dc; the generator is ac.
d)
The battery is ac; the generator is dc.
60.
What does it mean to say that a certain current is 60 Hz?
a)
It alternates back and forth 120 times a second.
b)
It alternates back and forth 60 times a second.
c)
It alternates back and forth 60 times an hour.
d)
It alternates back and forth 60 times a minute.
61.
What property of a diode enables it to convert ac to pulsed dc?
a)
It changes the frequency of the current from 60 Hz to 1 Hz.
b)
It is a transformer that changes the voltage of the current.
c)
It squares the ac current, thereby producing 120 dc pulses per second.
d)
It is a one-way valve that allows electrons to in one direction only.
62.
A diode converts ac to pulsed dc. What electrical device smoothes the pulsed dc to a smoother dc?
a)
A coupled diode called a triode
b)
A battery
c)
A resistor
d)
A capacitor
63.
What does the power company provide to our homes?
a)
It provides energy to move the electrons.
b)
It provides electrons that travel through the wire.
c)
It provides neither electrons nor the energy to move the electrons.
d)
It provides electrons and the energy to move the electrons.
64.
Of what physical quantity is Hertz a unit of?
a)
time taken by electrons as they travel down the wire
b)
number of times per second that the electrons move back and forth in the wire
c)
speed at which the electrons travel down the wire
65.
What type of field causes the electrons to do what they do in the wire?
a)
magnetic field
b)
electric field
c)
electric and magnetic fields.
66.
What kind of current runs through the electric wiring in a home?
a)
direct current
b)
alternating current
c)
circular current
67.
At what speed do electrons in a battery driven automotive circuit travel along a wire? At what speed does the electric field propagate along a wire?
a)
Electrons travel at a few million km/hr. The electric field propagates at the speed of light.
b)
Electrons move at 0.01 cm/s. The electric field propagates at nearly the speed of light.
c)
Electrons travel at 0.01 cm/s. The electric field travels instantaneously.
d)
Electrons move at the speed of light. The electric field moves at 0.01 cm/s.
68.
Why does a wire that carries electric current become hot?
a)
Moving electrons collide with atoms, which transfers their kinetic energy to atomic motion.
b)
Electrons collide with other electrons and the collisions produce sparks that heat the wire.
c)
Every time an electron changes direction in an ac circuit, it pushes on nearby atoms, which makes them move. Dc current does not heat the wire.
d)
The electric field producing the current pushes on the atoms, which makes them move.
69.
What is meant by drift velocity?
a)
The velocity of the electric field in a wire.
b)
The collision velocity between electrons in the wire.
c)
The random motions of electrons moving a few million km/hr.
d)
The net flow of electrons along a wire.
70.
When you make your household electric payment at the end of the month, are you billed for voltage, current, power, or energy?
a)
Current
b)
Voltage
c)
Power
d)
Energy
71.
Electrons in the filament of a lamp that carries ac have a net speed that is
a)
very low, about a snail's pace
b)
about the speed of sound
c)
about the speed of light
d)
zero
72.
In a circuit of two lamps in series, where the current through one lamp is 1 A, what is the current through the other lamp? Defend your answer.
a)
1 amp. The same current flows through lamps in series.
b)
-1 amp. The sum of the currents must be zero.
c)
2 amps. The currents add in a series circuit.
d)
½ amp. The current is split equally between two lamps in series.
73.
Consider the power dissipated by two circuits with bulbs that are all identical to each other. One circuit contains three builbs in series, and the other circuit contains three bulbs in parallel. The ratio of power dissipation in the parallel circuit to that in the series circuit is
a)
1/9
b)
1
c)
9
d)
1/3
e)
3
74.
If a voltage of 6 V is impressed across the circuit in the preceding question and the voltage across the first lamp is 2 V, what is the voltage across the second lamp? Defend your answer.
a)
4 volts. The sum of the voltages across each lamp must add up to the total voltage across both lamps.
b)
2 volts. The voltages across two lamps in series must be the same.
c)
-8 volts. The voltages must sum to zero around a circuit.
d)
8 volts. Voltages in series add together.
75.
In a circuit of two lamps in parallel, where there is a voltage of 6 V across one lamp, what is the voltage across the other lamp?
a)
-6 volts
b)
3 volts
c)
6 volts
d)
9 volts
76.
Compared with a simple galvanometer, an electric motor is
a)
a complicated voltmeter
b)
different in that it is a source of voltage
c)
much the same with small modifications
d)
fundamentally different
77.
How does a galvanometer detect electric current?
a)
A magnetic compass is deflected when current flows through a coil surrounding the compass.
b)
An electric current flows through a wire in a magnetic field. The deflection force on the wire acts against a spring. The compression of the spring is proportional to current.
c)
The galvanometer counts electrons flowing through a wire. Each electron makes a click as it crosses the magnetic field.
d)
The galvanometer uses the contraction of a frog's leg to measure current.
78.
Between a watt, a kilowatt, and a kilowatt-hour, which is a unit of power and which is a unit of energy?
a)
A watt is power, a kilowatt is energy, and a kilowatt-hour is energy.
b)
A watt is power, a kilowatt is power, and a kilowatt-hour is energy.
c)
A watt is power, a kilowatt is energy, and a kilowatt-hour is power.
d)
A watt is energy, a kilowatt is energy, and a kilowatt-hour is power.
79.
The magnetic field about a straight length of current-carrying wire is
a)
aligned from north to south poles in the wire
b)
in accord with the inverse-square law
c)
similar to the shape of an electric field about a charged wire
d)
circular in shape
80.
At the micro level, what is the difference between an unmagnetized iron nail and a magnetized iron nail?
a)
An unmagnetized nail is made of hard iron. A magnetized nail is made from soft iron.
b)
An unmagnetized nail is made of an isotope of iron that is not magnetic. A magnetized nail is made from a magnetic isotope.
c)
In an unmagnetized nail, the magnetic domains have a random orientation so that the net magnetism adds to zero. In a magnetized nail, many of the magnetic domains are aligned.
d)
An unmagnetized nail is made of iron at low temperatures. A magnetized nail is made from iron that is hot.
81.
Which of the following are creatures that are known to harbor tiny magnets within their bodies?
a)
Bacteria, pigeons, bees, wasps, monarch butterflies, and sea turtles
b)
Bacteria, humans, bees, jellyfish, spiders, and sea horses
c)
Horses, sparrows, bees, jellyfish, cats, and anteaters
d)
Ants, bees, crickets, spiders, lions, and bears
82.
What are magnetic pole reversals?
a)
Bringing a stronger magnet near a weaker one causes the weaker one's poles to reverse.
b)
The magnetic field of the Sun is stronger than the magnetic field of Earth, so the reversal of the Sun's magnetic field forces the Earth's magnetic field to reverse, too.
c)
When new data is presented, scientists have to reverse their opinions on what is the origin of the Earth's magnetic field.
d)
The poles of the Earth's magnetic field undergo reversals.
83.
What is a magnetic domain?
a)
Clusters of atoms with their magnetic fields aligned
b)
Clusters of atoms with their magnetic fields not aligned
c)
Clusters of atoms where every atom has an opposing magnetic field
d)
Clusters of atoms with only north poles
84.
When the filament breaks in one lamp in a parallel circuit, lamps in other branches of the circuit normally
a)
continue glowing as brightly
b)
absorb energy from the damaged lamp
c)
go out
d)
continue glowing, but dimmer
85.
The entity that travels about the speed of light in an electric circuit is
a)
current
b)
voltage and electric field, but not current
c)
electric field
d)
voltage
86.
What is the source of the magnetic force?
a)
Electric charges in motion are the sources of magnetic forces.
b)
Stationary electrons are the source of magnetic forces.
c)
Magnetic poles in motion are the only source of magnetic forces.
d)
Spinning protons are the source of all magnetic forces.
87.
What kinds of appliances work on the principle of deflection of a current-carrying wire in a magnetic field?
a)
electric motor
b)
electric generator
c)
both an electric generator and an electric motor
88.
Why is the magnetic field strength greater inside a current-carrying loop of wire than about a straight section of wire?
a)
Electrons going around a loop align their spins and their individual magnetic fields with the fields of adjacent electrons.
b)
The magnetic field of each segment of wire in the loop, due to electrons moving in the wire, adds together inside the loop, thereby making the field become bunched-up.
c)
Each time an electron goes around the loop, it adds its magnetic field to the magnetic field of the loop, and each single electron goes around the loop many times.
d)
Negative electrons move in one direction around the loop, while positive protons move in the opposite direction, and their magnetic fields add inside the loop.
89.
When the filament breaks in one lamp in a series circuit, other lamps in the circuit normally
a)
go out
b)
absorb energy from the damaged lamp
c)
continue glowing as brightly
d)
continue glowing, but dimmer
90.
How is the magnetic force on a particle moving in a magnetic field different from gravitational and electric forces.
a)
Gravitational and electric forces are proportional to the inverse square of distance, whereas magnetic deflection forces are inversely proportional to distance.
b)
Gravitational and electric forces act along the line connecting two interacting objects, whereas magnetic forces are perpendicular to the motion of the particle and the magnetic field.
c)
Gravitational and electric forces can be shielded, whereas magnetic forces cannot.
d)
Gravitational and electric forces are proportional to the product of either mass or charge, whereas magnetic deflection forces are inversely proportional to the pole strengths.
91.
How does the heat emitted by lamps affect their efficiency?
a)
Heat emitted warms the air and increases the efficiency.
b)
Heat emitted reduces the efficiency.
c)
The efficiency depends only on the light emitted. It does not depend on the heat emitted at all.
d)
Emitted heat cools the lamp, thereby increasing its efficiency.
92.
Magnetic domains are composed of clustered
a)
iron atoms in random directions
b)
aligned iron atoms
c)
crystals of iron ions
d)
electrically charged iron atoms
93.
What effect does Earth's magnetic field have on the intensity of cosmic rays striking Earth's surface?
a)
It reduces the intensity near the poles and increases it at the equator.
b)
It increases the intensity.
c)
It reduces the intensity.
d)
It does not change the intensity.
94.
How is the rule for the interaction between magnetic poles similar to the rule for the interaction between electrically charged particles?
a)
Like poles repel, unlike poles attract, and the force is proportional to the distance between two poles. of the distance between two poles.
b)
Like poles repel, unlike poles attract, and the force is proportional to the inverse square of the distance between two poles.
c)
Like poles repel, unlike poles attract, and the force is inversely proportional to the distance between two poles.
d)
Like poles attract, unlike poles repel, and the force is proportional to the inverse square
95.
The fundamental rule for the attraction and repulsion of magnets is that
a)
magnetic forces follow the inverse-square law
b)
magnetic poles attract other magnetic poles
c)
opposite charges attract each other and like charges repel
d)
like poles repel each other while opposite poles attract
96.
What produces a magnetic field?
a)
Magnetic monopoles
b)
Voltage
c)
Electric dipoles
d)
Electric charges in motion
97.
In what way are magnetic poles very different from electric charges?
a)
Magnetic poles only attract. Electric charges can attract or repel.
b)
All magnets have both south and north poles. Electric charges can exist as singular entities.
c)
Magnetic poles can exist as singular entities called magnetic monopoles. Electric charges are always paired as dipoles.
d)
The magnetic force between two poles is not the inverse square.
98.
The source of a magnetic field is a moving
a)
magnetic south pole only
b)
magnetic north or south pole
c)
magnetic north pole only
d)
electron
99.
What happens when a switch is closed in a circuit that contains a battery and a wire that is placed between the poles of a magnet? See figure.
a)
Nothing happens. The wire will stay where it is.
b)
The wire will either bend up or down between the poles of the magnet due to the force of the magnetic field.
c)
The wire will fall under the force of gravity.
100.
The magnetic field about Earth takes a shape
a)
of an interior current-carrying coil
b)
similar to that of an interior bar magnet
c)
that conforms to the inverse-square law
d)
of the field about a straight-length of current-carrying wire
101.
The force that acts on a current-carrying wire placed in a magnetic field is
a)
opposite in direction to the magnetic field
b)
perpendicular or parallel depending on the orientation of the field
c)
perpendicular in direction to the magnetic field
d)
parallel in direction to the magnetic field
102.
The force that acts on an electron traveling in a magnetic field is
a)
parallel in direction to the magnetic field
b)
perpendicular or parallel depending on the orientation of the field
c)
perpendicular in direction to the magnetic field
d)
opposite in direction to the magnetic field
103.
In what direction relative to a magnetic field does a charged particle move in order to experience maximum deflecting force? To experience minimum deflecting force?
a)
Perpendicular for minimum force, parallel for maximum force
b)
Perpendicular for maximum force, parallel for minimum force
c)
Parallel for maximum force, antiparallel for minimum force
d)
Circling a field line for minimum force, along a field line for maximum force
104.
What is the relationship among electric power, current, and voltage?
a)
Power is current times voltage.
b)
Power is voltage.
c)
Power is voltage divided by current.
d)
Power is current divided by voltage.
105.
What two kinds of motion do electrons in an atom appear to have?
a)
Revolution and spin
b)
Linear and rotational
c)
Circular and oscillatory
d)
Linear and oscillatory
106.
When an iron rod is placed inside a current-carrying coil of wire
a)
the coil becomes an electromagnet
b)
the coil becomes a stronger electromagnet
c)
more current is required to increase its magnetic strength
d)
only then does the coil have a north and south magnetic pole
107.
How do the currents through the branches of a simple parallel circuit compare with the current in the voltage source?
a)
The current through the source plus the current through one of the branches equal the current through the other branch.
b)
The difference of the currents through the two branches equals the current through the source.
c)
The sum of the currents in the branches is equal and opposite to the current through the source.
d)
The sum of the currents in the branches equals the current through the source.
108.
How does magnetic field strength relate to the closeness of magnetic field lines about a bar magnet?
a)
The field strength is zero outside the magnet.
b)
The field strength is stronger where the field lines are closer.
c)
The field strength is weaker where the field lines are closer.
d)
The field strength does not depend on the spacing of the field lines.
109.
Why does a piece of iron in a current-carrying loop increase the magnetic field strength?
a)
The iron acts as a capacitor and stores spinning electrons, thus increasing the magnetic field.
b)
The electromagnetic field of the current-carrying loop is amplified because it aligns the domains in the iron.
c)
The iron is a permanent magnet and adds to the field of the current-carrying loop.
d)
The presence of the iron decreases the resistance in the current-carrying loop, thereby allowing more current to flow.
110.
In Chapter 22, we learned that the direction of the electric field about a point charge is radial to the charge. What is the direction of the magnetic field surrounding a current-carrying wire?
a)
The magnetic field is directed along concentric circles surrounding the wire.
b)
The magnetic field is radial to the wire pointing toward the wire.
c)
The magnetic field is parallel to the wire.
d)
The magnetic field is radial to the wire pointing away from the wire.
111.
What happens to the direction of the magnetic field about an electric current when the direction of the current is reversed?
a)
The magnetic field reverses direction at every point. A clockwise pattern of concentric circles becomes a counterclockwise pattern of concentric circles and vice versa.
b)
The magnetic field rotates through 90 degrees at every point. A clockwise pattern of concentric circles becomes a radial outward pattern, while a counterclockwise pattern becomes radially inward.
c)
The magnetic field parallel to the wire reverses direction, so fields parallel to the current become antiparallel and vice versa.
d)
The radial magnetic field reverses direction. Inward pointing fields become outward pointing and vice versa.
112.
What happens to the shape of a wire that is part of a circuit with a battery when the switch is closed and the battery voltage is increased? See figure.
a)
The wire bends more than it did before..
b)
The shape does not change.
c)
The wire becomes more horizontal; that is, the wire bends less
113.
What relative direction between a magnetic field and a current-carrying wire results in the greatest force?
a)
The wire should be perpendicular to the field.
b)
The wire should be parallel to the field.
c)
The wire should make a 45-degree angle to the field.
d)
The wire should be antiparallel to the field.
114.
What happens to the shape of a wire that is part of a circuit with a battery when the switch is closed and the direction of the current is reversed in the wire? See figure.
a)
The wire will bend less, but in the same direction.
b)
The wire will bend the same amount but in the opposite direction.
c)
The shape of the wire will not change.
d)
The wire will bend more, but in the same direction.
115.
The force between electrically charged particles depends on the magnitude of each charge, their separation distance, and what else?
a)
Their motion
b)
Their resistance
c)
Their temperature
d)
Their polarity
116.
What is the function of fuse or circuit breaker in a circuit?
a)
To prevent under loading a circuit with current
b)
To provide an extra burst of current when it is needed
c)
To prevent rapidly changing currents in the circuit
d)
To prevent over loading the circuit with current
117.
Why will dropping an iron magnet on a concrete sidewalk make it a weaker magnet?
a)
Vibrations due to the collision recrystallize the iron, thereby cancelling the magnetism.
b)
General relativity applies in free fall and cancels the magnetic field.
c)
The collision with the sidewalk momentarily heats the iron to incandescent temperatures that erase the alignment of the magnetic fields of the domains.
d)
Vibrations provide energy to randomize the magnetic directions of the domains.
118.
What is a galvanometer called when it has been calibrated to read current? When it has been calibrated to read voltage?
a)
Voltmeter, ammeter
b)
Ohmmeter, wattmeter
c)
Ammeter, voltmeter
d)
Wattmeter, ohmmeter
119.
Electric power in a circuit is the rate at which
a)
wattage dissipates
b)
current dissipates
c)
voltage dissipates
d)
energy dissipates
120.
Is it correct to say that an electric motor extends the physics that underlies a galvanometer? Why?
a)
Yes. The deflection forces are the same, but the direction of current in the galvanometer is reversed cyclically.
b)
No. The galvanometer uses a permanent magnet, whereas the motor uses no permanent magnet.
c)
Yes. The deflection forces are the same, but the direction of current in the motor is reversed cyclically.
d)
Yes. They were both invented by Galvani.
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