Deck 8: Static and Current Electricity

Question 1

Compared to the mass of a proton, the mass of the electron is

A)very much less.
B)identical.
C)greater.

Answer 1

A

Question 2

A positive ion has a deficiency of

A)electrons.
B)neutrons.
C)negative ions.

Answer 2

A

Question 3

An electron and a proton

A)attract each other.
B)repel each other.
C)attract or repel depending on distance.

Answer 3

A

Question 4

If you strip electrons from an atom, the atom becomes a

A)positive ion.
B)negative ion.
C)different element.

Question 5

A negatively charged rod is brought near a metal can that rests on a wood table. You touch the opposite side of the can momentarily with your finger. The can then becomes

A)positively charged.
B)negatively charged.
C)uncharged.

Question 6

The number of protons in the nucleus of an electrically neutral atom is equal to the number of

A)electrons that surround the nucleus.
B)neutrons in the nucleus.
C)both
D)neither

Question 7

The fundamental force underlying all chemical reactions is

A)gravitational.
B)nuclear.
C)centripetal.
D)electrical.
E)none of the above

Question 8

To say that electric charge is conserved is to say that electric charge

A)may occur in an infinite variety of quantities.
B)is a whole-number multiple of the charge of one electron.
C)will interact with neighboring electric charges.
D)can neither be created nor destroyed.

Question 9

A pair of positively-charged plastic straws tend to

A)attract each other.
B)repel each other.
C)neutralize each other.

Question 10

A rubber rod rubbed with fur becomes

A)positively charged.
B)negatively charged.
C)both
D)neither.

Question 11

A difference between an insulator and a conductor is that a conductor has more

A)electrons than protons.
B)protons than electrons.
C)energy than an insulator.
D)faster moving molecules.
E)none of the above

Question 12

When you remove electrons from a metal cup, the cup becomes

A)negatively charged.
B)positively charged.
C)ionized.

Question 13

The electric charge on all electrons

A)vary from atom to atom.
B)vary from ion to ion.
C)are identical.

Question 14

The unit of electric charge, the coulomb, is the charge on

A)one electron.
B)one proton.
C)a specific large number of electrons.

Question 15

When you scuff electrons from a carpet onto your feet, you become

A)negatively charged.
B)positively charged.
C)polarized.
D)ionized.
E)neutralized.

Question 16

Charge carriers in a metal are electrons rather than protons because electrons are

A)negative.
B)smaller.
C)loosely bound.
D)all of the above
E)none of the above

Question 17

Which force binds atoms together to form molecules?

A)gravitational
B)nuclear
C)electric
D)centripetal
E)none of the above

Question 18

The nucleus of an atom is charged

A)positively.
B)negatively.
C)both
D)none of the above

Question 19

As you comb your hair, electrons are rubbed onto the comb, which becomes

A)negatively charged.
B)positively charged.
C)ionized.

Question 20

To say that electric charge is conserved means that no case has ever been found where

A)the net charge on an object has changed.
B)the net amount of charge on an object has increased.
C)net charge has been created or destroyed.
D)none of the above

Question 21

A water molecule is electrically

A)polarized.
B)conducting.
C)insulating.
D)charged.

Question 22

Two charges separated by 1 m exert a 1.0-N force on each other. If the charges are pulled to a 3-m separation distance, the force on each charge will be

A)0.33 N.
B)0.11 N.
C)0 N.
D)3 N.
E)9 N.

Question 23

One main difference between gravitational and electric forces is that electric forces

A)attract.
B)repel or attract.
C)obey the inverse-square law.
D)act over shorter distances.
E)are weaker.

Question 24

The electric force between charges depends on the

A)magnitude of electric charges.
B)separation distance between electric charges.
C)both
D)none of the above

Question 25

Two charges separated by 1 m exert a 1.0-N force on each other. If the charges are pushed to 0.25-m separation, the force on each charge will be

A)1 N.
B)2 N.
C)4 N.
D)8 N.
E)16 N.

Question 26

Two charged particles near each other are released. As the particles move, the velocity of each increases. Therefore, the particles have

A)the same sign.
B)the opposite sign.
C)not enough information

Question 27

Food cooked in a microwave oven depends on electrical

A)conduction.
B)charge polarization.
C)resistance changes.
D)field strength.
E)all of the above

Question 28

Two charged particles near each other are released. As they move, the force on each particle increases. Therefore, the particles have

A)the same sign.
B)the opposite sign.
C)not enough information

Question 29

The direction of an electric field is defined as the direction of force on a

A)charged particle.
B)a positively-charged particle.
C)a negatively-charged particle.

Question 30

A balloon will stick to a wooden wall if the balloon is charged

A)negatively.
B)positively.
C)either
D)neither

Question 31

A positive and a negative charge near each other are released. As they move, the force on each particle

A)increases.
B)decreases.
C)stays the same.

Question 32

A difference between electric and gravitational forces is that electric forces include

A)separation distance.
B)repulsive interactions.
C)the inverse-square law.
D)infinite range.
E)none of the above

Question 33

What are the similarities and differences between Coulomb's law and Newton's law of gravitation?

Question 34

A negatively-charged balloon touching a wooden wall

A)pulls positive charge on the wall surface toward it.
B)pushes negative charge in the wall away from it.
C)polarizes molecules in the wall.
D)all of the above
E)none of the above

Question 35

To say that an object is electrically polarized is to say

A)it is electrically charged.
B)its charges have been rearranged.
C)its internal electric field is zero.
D)it is only partially conducting.
E)it is to some degree magnetic.

Question 36

When the distance between two charges is halved, the electric force between the charges

A)quadruples.
B)doubles.
C)is half.
D)is reduced by one-quarter.
E)none of the above

Question 37

The electric force between charges is strongest when the charges are

A)close together.
B)far apart.
C)either

Question 38

Two charged particles repel each other will a force F. If the charge on one particle is doubled and the distance between them is doubled, the force will be

A)F.
B)2 F.
C)F/2.
D)F/4.
E)none of the above

Question 39

Two charges separated by 1 m exert a 1-N force on each other. If the magnitude of each charge is doubled, the force on each charge will be

A)1 N.
B)2 N.
C)4 N.
D)8 N.
E)none of the above

Question 40

An electrically polarized object normally has

A)a net charge of zero.
B)displaced charges.
C)both
D)neither

Question 41

Just as water flows from high to low pressure, electric charge flows from

A)high to low voltage.
B)high charge concentration to low charge concentration.
C)high resistance to low resistance.
D)all of the above
E)none of the above

Question 42

When a battery does 24 J of work on 10 C of charge, the voltage it supplies is

A)2.4 V.
B)4.2 V.
C)24 V.
D)240 V.
E)none of the above

Question 43

An electron is pushed into an electric field where it acquires a 1-V electric potential. If two electrons are pushed the same distance into the same electric field, the electric potential of both electrons is

A)0.25 V.
B)0.5 V.
C)1 V.
D)2 V.
E)4 V.

Question 44

Measurements show there is an electric field surrounding the Earth. Its magnitude averages 100 N/C at the Earth's surface and it points inward toward the Earth's center. From this information, state whether the Earth is negatively or positively charged. Defend your answer.

Question 45

Which is more dangerous, touching a faulty 120-V light fixture, or a Van de Graaff generator charged to 100,000 V?

A)light fixture
B)generator
C)both equally

Question 46

If you do 10 J of work to push 1 coulomb of charge into an electric field, its voltage with respect to its starting position is

A)less than 10 V.
B)10 V.
C)more than 10 V.

Question 47

Electric potential energy is measured in units of

A)volts.
B)joules.
C)amperes.
D)watts.
E)any or all of these

Question 48

The flow of charge in a circuit depends on

A)adequate resistance.
B)a potential difference.
C)adequate chemical action.
D)all of the above

Question 49

If you do 10 J of work to push a charge into an electric field and then release the charge, as it flies past its starting position, its kinetic energy is

A)less than 10 J.
B)10 J.
C)more than 10 J.

Question 50

Electric potential is measured in units of

A)volts.
B)joules.
C)amperes.
D)watts.
E)any or all of these

Question 51

Lillian touches a 100,000-V Van de Graaff generator with little harm because although the voltage is high, the relatively small amount of charge means there is a relatively small

A)amount of energy.
B)electric field.
C)polarization.
D)conduction.

Question 52

A proton and an electron are placed in an electric field. Which undergoes the greater acceleration?

A)the electron
B)the proton
C)both equally
D)neither

Question 53

Electric field lines about a point charge extend

A)outward when the charge is negative.
B)outward when the charge is positive.
C)in circles.

Question 54

The purpose of a voltage source is to provide an electrical

A)energy sink.
B)field.
C)pressure.

Question 55

A charged balloon illustrates that something can have a great amount of

A)potential energy and a low voltage.
B)voltage and a small potential energy.
C)both voltage and potential energy.
D)none of the above

Question 56

The reason that Lillian's hair stands out when her hand is on a charged Van de Graaff generator is

A)strands of hair become charged and repel one another.
B)a high voltage is communicated to strands of hair.
C)strands of hair find themselves in an electric field.
D)electrons and protons are deposited on her hair.

Question 57

The electric force on a 2-C charge is 60 N. How great is the electric field at the charge location?

A)20 N/C
B)30 N/C
C)60 N/C
D)120 N/C
E)240 N/C

Question 58

The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is

A)half as much.
B)the same.
C)twice as much.
D)four times as much.
E)none of the above

Question 59

Every proton in the universe is surrounded by its own

A)electric field.
B)gravitational field.
C)both
D)none of the above

Question 60

Normally a balloon charged to several thousand volts has a relatively small amount of

A)charge.
B)energy.
C)both
D)neither

Question 61

When a light switch is turned on in a dc circuit, the average speed of electrons in the lamp is

A)the speed of sound waves in metal.
B)the speed of light.
C)1000 cm/s.
D)less than 1 cm/s.
E)dependent on how quickly each electron bumps into the next electron.

Question 62

Compared to the work input to charge an electrostatic generator, the energy output is

A)less.
B)more.
C)no more.

Question 63

A coulomb of charge passing through a 6-V battery supplies

A)6 joules.
B)6 amperes.
C)6 ohms.
D)6 watts.
E)6 newtons.

Question 64

The electric charge on a current-carrying wire is normally

A)zero.
B)equal and opposite to the charge within the wire.
C)the voltage divided by the resistance.

Question 65

The source of electrons in an ordinary electric circuit is

A)a dry cell, wet cell, or battery.
B)usually a wall socket.
C)a generator at the power station.
D)the electric conductor itself.
E)none of the above

Question 66

Electrons flow in a wire when there is

A)an imbalance of charges in the wire.
B)more potential energy at one end of the wire than the other end.
C)a potential difference across its ends.

Question 67

The amount of energy given to each coulomb of charge flowing through a 12-V battery is

A)12 J.
B)12 A.
C)12 V.
D)all of the above
E)none of the above

Question 68

A sustained electric current can be achieved with a

A)generator.
B)battery.
C)both
D)none of the above

Question 69

To say a circuit is dc is to say that current in the circuit

A)has a single direction.
B)alternates only slowly.
C)is parallel to the connecting wires.

Question 70

The source of electrons lighting an incandescent ac light bulb is

A)the power company.
B)the electric outlet.
C)atoms in the light bulb filament.
D)the wire leading to the lamp.
E)the source voltage.

Question 71

Which statement is correct?

A)voltage flows through a circuit
B)voltage flows across a circuit
C)voltage is impressed across a device in a circuit

Question 72

In a common dc circuit, electrons typically move at the speed of

A)a fraction of a centimeter per second.
B)a few meters per second.
C)sound.
D)light.
E)none of the above

Question 73

A sustained flow of electric charge requires

A)a potential difference.
B)a resistance.
C)an electric field.
D)electric polarization.

Question 74

The electric current in a copper wire is normally composed of

A)electrons.
B)protons.
C)ions.
D)all or any of the above

Question 75

An ampere is a unit of electric

A)pressure.
B)current.
C)resistance.
D)all of the above
E)none of the above

Question 76

Electric charge will flow in an electric circuit when

A)electric resistance is low.
B)a potential difference exists.
C)the circuit is grounded.
D)electric devices in the circuit are not defective.

Question 77

Which statement is correct?

A)charge flows through a circuit
B)voltage flows through a circuit
C)resistance is established across a circuit
D)current causes voltage

Question 78

A term for electric pressure is

A)current.
B)voltage.
C)electric resistance.

Question 79

The electric field in the wires of an ac circuit

A)changes via the inverse square law.
B)changes direction with time.
C)remains relatively constant.
D)is nonexistent.
E)none of the above

Question 80

A flow of electrons move in an electric circuit by

A)bumping other electrons.
B)colliding with molecules.
C)interacting with an established electric field.
D)none of the above