Deck 22: Electrostatics

Question 1

The primary purpose of a lightning rod is to

A)attract lightning and guide it to the ground.
B)discharge the structure to which it is attached.
C)cancel the electric field within the structure to which it is attached.
D)induce a charge opposite to that of charged clouds overhead.

Answer 1

discharge the structure to which it is attached.

Question 2

The electrical force between charges is strongest when the charges are

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

Answer 2

close together.

Question 3

A transistor is an example of a

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

Answer 3

semiconductor.

Question 4

Superconductors are noted for their

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

Question 5

Use the following figure to answer the question:
A balloon will stick to a wooden wall if the balloon is charged

A)negatively.
B)positively.
C)either positively or negatively.
D)None of the above choices are correct.

Question 6

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 be neither created nor destroyed.
E)is sometimes negative.

Question 7

An electron and a proton

A)attract each other.
B)repel each other.
C)neither attract nor repel each other.

Question 8

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

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 be neither created nor destroyed.
E)is sometimes positive.

Question 9

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 10

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

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

Question 11

Which force binds atoms together to form molecules?

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

Question 12

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 13

Strip electrons from an atom and the atom becomes a

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

Question 14

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

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

Question 15

The electrical force between charges depends only on the charges'

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

Question 16

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

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

Question 17

The fundamental force underlying all chemical reactions is

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

Question 18

Rub electrons from your hair with a comb and the comb becomes

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

Question 19

A positive ion has more

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

Question 20

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

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

Question 21

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

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

Question 22

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

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

Question 23

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

A)quadruples.
B)doubles.
C)halves.
D)is reduced by 1/4.
E)None of the above choices are correct.

Question 24

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

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

Question 25

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

Question 26

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

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

Question 27

In the unlikely case of a lightning strike,it is worse to be inside a building framed with

A)steel.
B)iron.
C)aluminum.
D)wood.

Question 28

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

Question 29

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

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

Question 30

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

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

Question 31

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 32

Particle A has twice the charge of nearby particle B.Compared to the force on Particle A,the force on Particle B is

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

Question 33

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 choices are correct.

Question 34

A conductor differs from an insulator in that a conductor

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

Question 35

An electroscope is charged positively as shown by foil leaves that stand apart.As a negative charge is brought close to the electroscope,the leaves

A)fall closer together.
B)spread apart further.
C)do not move.

Question 36

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

Question 37

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

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

Question 38

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

Question 39

The net charge on a charged capacitor depends on

A)the area of the capacitor plates.
B)the distance between the capacitor plates.
C)the medium between the capacitor plates.
D)All of the above choices are correct.
E)None of the above choices are correct - the net charge is zero.

Question 40

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

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

Question 41

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/2.
D)F/4.
E)none of these

Question 42

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)30 N/C
C)60 N/C
D)120 N/C
E)240 N/C

Question 43

The electric field inside an uncharged metal ball is zero.If the ball is negatively charged,the electric field inside the ball is then

A)less than zero.
B)zero.
C)greater than zero.

Question 44

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

Question 45

Two charged particles held close to each other are released.As the particles move,the velocity of each increases.Therefore,their charges have

A)the same sign.
B)opposite signs.
C)either the same or opposite signs.
D)impossible to answer without additional information

Question 46

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

Question 47

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

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

Question 48

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)25 V.
B)0)5 V.
C)1 V.
D)2 V.
E)4 V.

Question 49

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

Question 50

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

Question 51

You can touch a 100,000-volt 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 amount of

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

Question 52

Two charges separated by one meter exert 1-N forces on each other.If the charges are pulled to 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 53

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 54

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 nor energy.

Question 55

Two charged particles held close to each other are released.As they move,the force on each particle increases.Therefore,the particles must have

A)the same sign.
B)opposite signs.
C)the same mass.
D)the same size.
E)impossible to answer without additional information

Question 56

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

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

Question 57

A highly charged child's balloon is not dangerous because

A)rubber is not a good conductor of electricity.
B)its outside surface is positively charged.
C)the potential difference between the balloon and the child's hand is very small.
D)None of the above choices are correct.

Question 58

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

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