Deck 10: Static and Current Electricity

Question 1

A positive ion has more

A) neutrons than protons.
B) protons than electrons.
C) protons than neutrons.
D) electrons than neutrons.
E) electrons than protons.

Answer 1

protons than electrons.

Question 2

The headlights, radio, and defroster fan in an automobile are connected in

A) series without separate switches.
B) series with a switch for each.
C) parallel with a switch for each.
D) parallel without separate switches.

Answer 2

parallel with a switch for each.

Question 3

There are electrons in the filament of the ac lamp in your bedroom. When you turn on the lamp and it glows, the glowing comes from

A) different electrons; the ones that flow in the circuit to your lamp.
B) the positive charges that flow in the filament.
C) the same electrons.

Answer 3

the same electrons.

Question 4

In a common dc circuit, electrons move at speeds of

A) the speed of light.
B) the speed of a sound wave.
C) many centimeters per second.
D) a fraction of a centimeter per second.
E) none of these

Question 5

An uncharged pith ball is suspended by a nylon fiber. When a negatively charged rubber rod is brought nearby, without touching it, the pith ball

A) becomes polarized.
B) is repelled by the rod.
C) becomes charged by induction.
D) in unaffected.
E) None of the above choices are correct.

Question 6

A circuit breaker often serves the same purpose as a

A) capacitor.
B) fuse.
C) battery
D) All of the above choices are correct.
E) None of the above choices are correct.

Question 7

A power line with a resistance of 2 ohms has a current of 80 A in it. The power dissipated in the line is

A) 160 W.
B) 320 W.
C) 12,800 W.
D) 40 W.
E) none of these

Question 8

If you comb your hair and the comb becomes positively charged, then your hair becomes

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

Question 9

Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will carry

A) more current.
B) less current.
C) the same current.

Question 10

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

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

Question 11

The number of electrons delivered daily to an average American home by an average power utility in the mid 1980s was

A) 220.
B) zero.
C) 110.
D) billions of billions.
E) none of these

Question 12

Normally a small party balloon charged to several thousand volts will have a relatively small amount of

A) charge and energy.
B) energy.
C) charge
D) neither charge or energy.

Question 13

The direction of an electric field is the direction of the force that the field would exert on

A) a neutral test charge.
B) a molecule.
C) an atom.
D) a proton.
E) an electron.

Question 14

Stretch a copper wire so that it is thinner and the resistance between its ends

A) remains unchanged.
B) decreases.
C) increases.

Question 15

Electric potential, measured in volts, is the ratio of electric energy to amount of electric

A) charge.
B) current.
C) resistance.
D) voltage.
E) None of the above choices are correct.

Question 16

Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have

A) less resistance.
B) more resistance.
C) the same resistance.

Question 17

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

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

Question 18

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

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

Question 19

Every proton in the universe is surrounded by its own

A) electric field and gravitational field.
B) gravitational field.
C) electric field
D) None of the above choices are correct..

Question 20

In a simple circuit containing a bulb, energy is given to the moving charges by

A) a generator.
B) the bulb.
C) the wires.
D) none of these

Question 21

Two lamps, one with a thick filament and one with a thin filament of the same material, are connected in series to a battery. The voltage is greater across the lamp with the

A) thin filament.
B) thick filament.
C) Voltage is the same for both.

Question 22

Electrons are made to flow in a wire when there is

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

Question 23

A conductor differs from an insulator in that a conductor

A) has faster moving molecules.
B) has more energy than an insulator.
C) has more protons than electrons.
D) has more electrons than protons.
E) none of these

Question 24

Which force binds atoms together to form molecules?

A) electrical
B) nuclear
C) centripetal
D) gravitational
E) none of these

Question 25

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

A) net charge has been created or destroyed.
B) total charge on an object has changed.
C) total amount of charge on an object has increased.
D) net amount of negative charges on an object is unbalanced by positive charge on another object.
E) None of the above choices are correct.

Question 26

An electrical diode is useful for

A) voltage modification.
B) boosting voltage.
C) storing electrical energy.
D) limiting current.
E) changing ac to dc.

Question 27

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

A) 10 V.
B) less than 10 V.
C) more then 10 V.
D) None of the above choices are correct.

Question 28

A heater uses 20 A when used in a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is

A) $5.50.
B) $2.20.
C) $0.55.
D) $0.22.
E) none of these

Question 29

The fundamental force underlying all chemical reactions is

A) nuclear.
B) electrical.
C) gravitational.
D) centripetal.
E) None of the above choices are correct..

Question 30

Compared to a single lamp connected to a battery, two identical lamps connected in series to the same battery will carry

A) less current.
B) more current.
C) the same current.

Question 31

The electrical force between charges is strongest when the charges are

A) far apart.
B) close together.
C) The electric force is constant everywhere.

Question 32

The power dissipated in a 4-ohm resistor carrying 3 A is

A) 48 W.
B) 36 W.
C) 7 W.
D) 18 W.
E) not enough information to say

Question 33

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

A) neutrons in the nucleus.
B) electrons that surround the nucleus.
C) Choices A and B are both correct.
D) Choices A and B are both incorrect.

Question 34

When two lamps are connected in parallel to a battery, the electrical resistance that the battery senses is

A) more than the resistance of either lamp.
B) less than the resistance of either lamp.
C) none of these

Question 35

Two protons attract each other gravitationally and repel each other electrically. By far the greater force is

A) the gravitational attraction.
B) the electrical repulsion.
C) neither - the forces are the same.

Question 36

A difference between electric forces and gravitational forces is that gravitational forces are not affected by

A) separation distance.
B) the inverse square law.
C) repulsive interaction.
D) infinite range.
E) None of the above choices are correct.

Question 37

Compared to the filament thickness of a 60-W light bulb, the filament of a 100-W light bulb will be

A) thinner.
B) thicker.
C) the same.

Question 38

Strip electrons from an atom and the atom becomes a

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

Question 39

In an ac circuit, the electric field

A) is everywhere the same.
B) changes magnitude and direction with time.
C) increases via the inverse square law.
D) is non-existent.
E) none of these

Question 40

The electrical force between charges depends only on the the charges

A) separation distance
B) magnitude .
C) magnitude and separation distance.
D) None of the above choices are correct.

Question 41

Two charges separated by one meter exert 1-N forces on each other. If the magnitude of each charge is doubled, the force on each charge is

A) 4 N.
B) 8 N.
C) 2 N.
D) 1 N.
E) None of the above choices are correct.

Question 42

A 60-W light bulb and a 100-W light bulb are connected in series to a 120 V outlet. Which light bulb has more current in it?

A) the 100-W bulb
B) the 60-W bulb
C) Both have the same current.

Question 43

Two lamps, one with a thick filament and one with a thin filament of the same material, are connected in parallel to a battery. The current is larger in the lamp with the

A) thin filament.
B) thick filament.
C) Current is the same in both.

Question 44

Two charged particles held near each other are released. As they move, the acceleration of each decreases. Therefore, the particles have

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

Question 45

An electric heater is rated at 300 W when used in a 110-V circuit. The safety fuse in the circuit can handle 15 A of current. How many heaters can be safely operated in the circuit?

A) 5
B) 3
C) 4
D) 2
E) more than 5

Question 46

Two charged particles attract each other with a force F. If the charges of both particles are doubled, and the distance between them also doubled, then the force of attraction will be

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

Question 47

The current through a 10-ohm resistor connected to a 120-V power supply is

A) 1 A.
B) 12 A.
C) 10 A.
D) 120 A.
E) none of these

Question 48

When a car is struck by lightning, the resulting electric field inside the car is

A) zero.
B) normally huge for a time longer than the lightning stroke itself.
C) small enough to be safe for an occupant inside.
D) normally huge, but for a brief time.

Question 49

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) four times as much.
B) half as much.
C) the same.
D) twice as much.
E) None of the above choices are correct.

Question 50

A negatively charged rod is held near a metal can that rests on a dry wood table. If you touch the opposite side of the can momentarily with your finger the can is then

A) negatively charged.
B) positively charged.
C) partially discharged.
D) completely discharged.
E) discharged only on the side touched.

Question 51

As more lamps are put into a series circuit, the overall current in the power source

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

Question 52

A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?

A) 5 V
B) 20 V
C) 10 V
D) 15 V
E) more than 20 V

Question 53

The ratio of the potential difference across a metallic conductor to the current in the conductor is known as

A) resistance.
B) electromagnetic force.
C) potential drop.
D) conductivity.
E) None of the above choices are correct.

Question 54

The electrical force on a 2-C charge is 60 N. What is the value of the electric field at the place where the charge is located?

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

Question 55

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

A) proton
B) electron
C) Both accelerate equally.
D) Neither accelerates.

Question 56

An ampere is a unit of electrical

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

Question 57

Assume that 10 J of work is needed to push a charge, at rest, into an electric field. After the charge is released there, it flies back to its starting position and its kinetic energy there will be

A) 5 J.
B) zero.
C) 10 J.
D) more than 10 J.
E) impossible to predict without additional information.

Question 58

Two charges separated by one meter exert 1-N forces on each other. If the charges are pushed to 1/4 meter separation, the force on each charge will be

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

Question 59

To say that electric charge is quantized is to say that the charge on an object

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

Question 60

After a capacitor is fully charged, the total number of electrons it contains

A) is much less.
B) is slightly less.
C) is slightly greater.
D) is much greater.
E) remains unchanged.

Question 61

Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The voltage is greatest across the lamp with the

A) thick filament.
B) thin filament.
C) Both voltages are the same.

Question 62

Two charged particles repel each other with a force F. If the charge of one of the particles is doubled and the distance between them is also doubled, then the force will be

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

Question 63

A capacitor is used to store

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

Question 64

A woman experiences an electrical shock. The electrons making the shock come from the

A) electric field in the air.
B) power plant.
C) hairdryer.
D) woman's body.
E) ground.

Question 65

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

A) a specific number of neutrons.
B) a neutron.
C) a quark.
D) a specific large number of electrons.
E) one electron.

Question 66

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

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

Question 67

The primary source of electrons in an ordinary electrical circuit is

A) the power station generator.
B) a dry cell, wet cell or battery.
C) the electrical circuit itself.
D) the back emf of motors.
E) none of these

Question 68

An electron and a proton

A) attract each other.
B) repel each other.
C) neither attract or repel each other.

Question 69

When a single charge q is placed at one corner of a square, the electric field at the center of the square is F/q. If two other equal charges are placed at the adjacent corners of the square, the electric
Field at the center of the square due to these three equal charges is

A) F/(2q).
B) 4F/q.
C) F/q.
D) F/(4q).
E) None of the above choices are correct.

Question 70

A transistor is an example of a

A) resistor.
B) semiconductor.
C) superconductor.
D) transmitter.
E) dry cell.

Question 71

A circuit is powered with a battery. Charge flows

A) through both the battery and the rest of the circuit.
B) from the negative battery terminal to the positive terminal.
C) out of the battery and into the circuit.
D) only after a couple seconds pass.
E) none of these

Question 72

As more lamps are put into a parallel circuit, the overall current in the power source

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

Question 73

Heat a copper wire and its electric resistance

A) decreases.
B) increases.
C) remains unchanged.

Question 74

A main difference between gravitational and electric forces is that electrical forces

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

Question 75

Superconductors are noted for their

A) bright colors.
B) absence of electric resistance.
C) low cost.
D) high electric resistance.
E) low electric resistance.

Question 76

The electric field inside the dome of a Van de Graaff generator

A) depends on the volume of the dome
B) depends on the amount of charge the outside of dome.
C) Choices A and B are both correct.
D) None of the above choices are correct..

Question 77

Alternating current is normally produced by a

A) battery.
B) generator.
C) both of these
D) neither of these

Question 78

A sphere has a negative charge of 6.4 × 10-7 coulomb. The approximate number of electrons that must be removed to make the sphere neutral is

A) 1.6 × 10-8.
B) 6.4 × 1026 .
C) 9.8 × 103.
D) 4.0 × 1012 .

Question 79

In an electric circuit, the safety fuse is connected to the circuit in

A) series.
B) parallel.
C) either series or parallel.

Question 80

Compared to the amount of electric current in the filament of a lamp, the amount of current in the connecting wire is

A) actually more.
B) the same.
C) often less.
D) definitely less.
E) incredibly, all of these.