Let's Review Regents: Physics—Physical Setting

Miriam A. Lazar

Chapter 8

Static Electricity - all with Video Answers

Educators

Chapter Questions

Problem 1

A glass rod becomes positively charged when rubbed with silk. The silk becomes charged because it
(A) 1oses protons
(B) loses electrons
(C) gains protons
(D) gains electrons

Stephen Zaffke

Stephen Zaffke

Numerade Educator

Problem 2

A potential difference of $10.0$ volts exists between two points, $A$ and $B$, within an electric field. What is the magnitude of charge that requires $2.0 \times 10^{-2}$ joule of work to move it from $A$ to $B$ ?
(A) $5.0 \times 10^{2} \mathrm{C}$
(B) $2.0 \times 10^{-1} \mathrm{C}$
(C) $5.0 \times 10^{-2} \mathrm{C}$
(D) $2.0 \times 10^{-3} \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 3

A negatively charged object is brought near the knob of a negatively charged electroscope. The leaves of the electroscope will(A) move closer together
(B) move farther apart
(C) become positively charged
(D) become neutral

Stephen Zaffke

Numerade Educator

Problem 4

A neutral rubber rod is rubbed with fur and acquires a charge of $2 \times 10^{-6}$ coulomb. The charge on the fur is
(A) $+1 \times 10^{-6} \mathrm{C}$
(B) $+2 \times 10^{-6} \mathrm{C}$
(C) $-1 \times 10^{-6} \mathrm{C}$
(D) $-2 \times 10^{-6} \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 5

Which diagram shows the leaves of an electroscope charged negatively by induction?(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 6

A small, uncharged metal sphere is placed near a larger, negatively charged sphere. Which diagram best represents the charge distribution on the smaller sphere?(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 7

When a rubber rod is rubbed with fur, the rod becomes negatively charged because of the transfer of
(A) electrons to the fur
(B) protons to the fur
(C) electrons to the rod
(D) protons to the rod

Stephen Zaffke

Numerade Educator

Problem 8

A charge of 10 elementary charges is equivalent to
(A) $1.60 \times 10^{-19} \mathrm{C}$
(B) $1.60 \times 10^{-18} \mathrm{C}$
(C) $6.25 \times 10^{18} \mathrm{C}$
(D) $6.25 \times 10^{19} \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 9

Sphere $A$ has a charge of $+2$ units and sphere $B$, which is identical to sphere $A$, has a charge of $-4$ units. If the two spheres are brought together and then separated, the charge on each sphere will be
(A) $-1$ unit
(B) $-2$ units
(C) $+1$ unit
(D) $+4$ units

Stephen Zaffke

Numerade Educator

Problem 10

The unit of charge in the SI system is the
(A) $\mathrm{ohm}$
(B) ampere
(C) coulomb
(D) volt

Stephen Zaffke

Numerade Educator

Problem 11

In the Millikan oil drop experiment, an oil drop is found to have a charge of $-4.8 \times 10^{-19}$ coulomb. How many excess electrons does the oil drop have?
(A) $1.6 \times 10^{-19}$
(B) 2
(C) 3
(D) $6.3 \times 10^{18}$

Stephen Zaffke

Numerade Educator

Problem 12

Two identical metal spheres, charged as shown in the diagram, are brought into contact and then separated.
What will be the charge on sphere $A$ after separation?
(A) $-1 \times 10^{-6} \mathrm{C}$
(B) $+1 \times 10^{-6} \mathrm{C}$
(C) $+6 \times 10^{-6} \mathrm{C}$
(D) $+12 \times 10^{-6} \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 13

A body will maintain a constant negative electrostatic charge if the body
(A) maintains the same excess of electrons
(B) maintains the same excess of protons
(C) continuously receives more electrons than it loses
(D) continuously receives more protons than it loses

Stephen Zaffke

Numerade Educator

Problem 14

A positively charged body must have(A) an excess of neutrons
(B) an excess of electrons
(C) a deficiency of protons
(D) a deficiency of electrons

Stephen Zaffke

Numerade Educator

Problem 15

A neutral object is attracted by a charged object because the neutral object's
(A) charges are redistributed
(B) charge is lost to the surroundings
(C) net charge is changed by induction
(D) net charge is changed by conduction

Stephen Zaffke

Numerade Educator

Problem 16

An electron is located in the electric field between two parallel metal plates as shown in the diagram below.

If the electron is attracted to plate $A$, then plate $A$ is charged(A) positively, and the electric field is directed from plate $A$ toward plate $B$
(B) positively, and the electric field is directed from plate $B$ toward plate $A$
(C) negatively, and the electric field is directed from plate $A$ toward plate $B$
(D) negatively, and the electric field is directed from plate $B$ toward plate $A$

Vishal Gupta

Numerade Educator

Problem 17

A rod is rubbed with wool. Immediately after the rod and wool have been separated, the net charge of the rod-wool system
(A) decreases
(B) increases
(C) remains the same

Stephen Zaffke

Numerade Educator

Problem 18

As shown in the diagram below, a charged rod is held near, but does not touch, a neutral electroscope.
The charge on the knob becomes(A) positive and the leaves become positive
(B) positive and the leaves become negative
(C) negative and the leaves become positive
(D) negative and the leaves become negative

Stephen Zaffke

Numerade Educator

Problem 19

An uncharged metal sphere is placed midway between spheres $A$ and $B$, represented in the diagram below.

Which diagram best represents the arrangement of the charges in the uncharged sphere?(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 20

The electrostatic force of attraction between two small spheres that are l.o meter apart is $\mathbf{F}$. If the distance between the spheres is decreased to $0.5$ meter, the electrostatic force will then be(A) $\frac{\mathbf{F}}{2}$
(B) $2 \mathbf{F}$
(C) $\frac{\mathbf{F}}{2}$
(D) $4 \mathbf{F}$

Stephen Zaffke

Numerade Educator

Problem 21

The distance between two point charges is tripled. Compared to the original force, the new electrostatic force between the charges is
(A) decreased to one-ninth
(B) decreased to one-third
(C) increased by a factor of 3
(D) increased by a factor of 9

Stephen Zaffke

Numerade Educator

Problem 22

The electrical force of attraction between two point charges is $\mathbf{F}$. The charge on one of the objects is quadrupled, and the charge on the other object is doubled. The new force between the objects is(A) 8 F
(B) $2 \mathbf{F}$
(C) $\frac{1}{2} F$
(D) $4 \mathbf{F}$

Stephen Zaffke

Numerade Educator

Problem 23

A point charge of $-1.0 \times 10^{-9}$ coulomb is located $5.0 \times 10^{-2}$ meter from another point charge of $+3.0 \times 10^{-9}$ coulomb. What is the magnitude of the electric force between the two point charges?
(A) $6.0 \times 10^{-17} \mathrm{~N}$
(B) $1.2 \times 10^{-15} \mathrm{~N}$
(C) $5.4 \times 10^{-7} \mathrm{~N}$
(D) $1.1 \times 10^{-5} \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 24

Two point charges 1 meter apart repel each other with a force of 9 newtons. What is the force of repulsion when these two charges are 3 meters apart?
(A) $1 \mathrm{~N}$
(B) $27 \mathrm{~N}$
(C) $3 \mathrm{~N}$
(D) $81 \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 25

If the magnitude of the charge on each of two positively charged objects is halved, the electrostatic force between the objects will
(A) decrease to one-half
(B) decrease to one-quarter
(C) decrease to one-sixteenth
(D) remain the same

Stephen Zaffke

Numerade Educator

Problem 26

Which procedure will double the force between two point charges?
(A) doubling the distance between the charges
(B) doubling the magnitude of one charge
(C) halving the distance between the charges
(D) halving the magnitude of one charge

Stephen Zaffke

Numerade Educator

Problem 27

The force between two fixed, charged spheres is $\mathbf{F}$. If the charge on each sphere is halved, the force between them will be
(A) $\mathbf{F}$
(B) $\frac{\mathbf{F}}{2}$
(C) $\frac{\mathbf{F}}{2}$
(D) $4 \mathbf{F}$

Stephen Zaffke

Numerade Educator

Problem 28

The diagram below represents two charges with a separation of $d$. Which step would produce the greatest increase in the force between the two charges?
(A) doubling charge $q_{1}$, only
(B) doubling $d$, only
(C) doubling charge $q_{1}$, only, and $d$
(D) doubling both charges and $d$

Stephen Zaffke

Numerade Educator

Problem 29

What is the magnitude of the electric field intensity at a point in space where a charge of 100 coulombs experiences a force with a magnitude of 10 newtons?
(A) $1 \mathrm{~N} / \mathrm{C}$
(B) $10 \mathrm{~N} / \mathrm{C}$
(C) $0.1 \mathrm{~N} / \mathrm{C}$
(D) $100 \mathrm{~N} / \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 30

Which is a vector quantity?
(A) electric energy
(B) electric charge
(C) electric power
(D) electric field intensity

Stephen Zaffke

Numerade Educator

Problem 31

The electric field intensity at a given distance from a point charge is $\mathbf{E}$. If the charge is doubled and the distance remains fixed, the electric field intensity will be
(A) $\frac{\mathbf{E}}{2}$
(B) $2 \mathbf{E}$
(C) $\frac{\mathbf{E}}{2}$
(D) $4 \mathbf{E}$

Stephen Zaffke

Numerade Educator

Problem 32

The electric field around a point charge is
(A) radial
(B) elliptical
(C) parabolic
(D) circular

Stephen Zaffke

Numerade Educator

Problem 33

Gravitational force is to mass as electrical force is to
(A) weight
(B) charge
(C) gravity
(D) electricity

Stephen Zaffke

Numerade Educator

Problem 34

As the electric field intensity at a point in space decreases, the electrostatic force on a unit charge at this point
(A) decreases
(B) increases
(C) remains the same

Stephen Zaffke

Numerade Educator

Problem 35

The diagram below shows some of the lines of electric force around a positive point charge.The strength of the electric field is
(A) greatest at point $A$
(B) greatest at point $B$
(C) greatest at point $C$
(D) equal at points $A, B$, and $C$

Stephen Zaffke

Numerade Educator

Problem 36

The diagram below represents a uniformly charged rod.
Which graph best represents the relationship between the magnitude of the electric field intensity $(E)$ and the distance from the rod as measured along line $A B$ ?(A) $t$
(B) $\epsilon$
(C) $\varepsilon /$
(D)
<smiles>[C+]1C=C1</smiles>

Stephen Zaffke

Numerade Educator

Problem 37

The diagram below represents an electron within an electric field between two parallel plates that are charged with a potential difference of $40.0$ volts.
If the magnitude of the electric force on the electron is $2.00 \times 10^{-}$ ${ }^{15}$ newton, the magnitude of the electric field strength between the charged plates is(A) $3.20 \times 10^{-34} \mathrm{~N} / \mathrm{C}$
(B) $2.00 \times 10^{-14} \mathrm{~N} / \mathrm{C}$
(C) $1.25 \times 10^{4} \mathrm{~N} / \mathrm{C}$
(D) $2.00 \times 10^{16} \mathrm{~N} / \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 38

What force will a proton experience in a uniform electric field whose strength is $2.00 \times 10^{5}$ newtons per coulomb?
(A) $8.35 \times 10^{24} \mathrm{~N}$
(B) $1.67 \times 10^{5} \mathrm{~N}$
(C) $3.20 \times 10^{-14} \mathrm{~N}$
(D) $1.67 \times 10^{-14} \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 39

A proton experiences an electrical force $\mathbf{F}$ when placed at a point in an electric field. If the proton is replaced by an electron, what force will the electron experience?
(A) $-\mathbf{F}$
(B) $-\mathbf{F} \frac{m_{p}}{m_{e}}$
(C) $\mathbf{F} \frac{m_{p}}{m_{e}}$
(D) $\mathbf{F}$

Stephen Zaffke

Numerade Educator

Problem 40

The energy gained by the charged sphere as it moves from the negative plate to the positive plate can be measured in(A) electron-volts
(B) volt-meters
(C) coulombs/volt
(D) volts/meter

Stephen Zaffke

Numerade Educator

Problem 41

As the sphere moves from the negative plate to the positive plate, the force on the sphere
(A) decreases
(B) increases
(C) remains the same

Stephen Zaffke

Numerade Educator

Problem 42

Gravitational forces differ from electrostatic forces in that gravitational forces are
(A) attractive, only
(B) repulsive, only
(C) neither attractive nor repulsive
(D) both attractive and repulsive

Stephen Zaffke

Numerade Educator

Problem 43

- Which diagram best illustrates the electric field between charges $A$ and $B ?$
(A)
(B)
(C) . Q $\gamma$.
(D)

Stephen Zaffke

Numerade Educator

Problem 44

The magnitude of the force of sphere $A$ on sphere $B$ is
(A) $1.2 \times 10^{-2} \mathrm{~N}$
(B) $2.0 \times 10^{3} \mathrm{~N}$
(C) $4.4 \times 10^{-13} \mathrm{~N}$
(D) $4.0 \times 10^{-3} \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 45

If another small sphere with a charge of $+2.0 \times 10^{-6}$ coulomb is placed at point $y$, the net force on this sphere will be
(A) $0 \mathrm{~N}$
(B) 40. N
(C) 8o. N
(D) $240 \mathrm{~N}$

Ivan Kochetkov

Numerade Educator

Problem 46

If a positive charge is placed at point $x$, the direction of the net force on the charge will be
(A) into the page
(B) out of the page
(C) toward the left
(D) toward the right

Stephen Zaffke

Numerade Educator

Problem 47

If sphere $A$ is moved toward sphere $B$, the electric field intensity at point $x$ will
(A) decrease
(B) increase
(C) remain the same
Base your answers to questions 48 and 49 on the information and diagram below.
Two small metallic spheres, $A$ and $B$, are separated by a distance of $4.0 \times 10^{-1}$ meter, as shown. The charge on each sphere is $+1.0 \times 10^{-6}$ coulomb. Point $P$ is located near the spheres.

Stephen Zaffke

Numerade Educator

Problem 48

What is the magnitude of the electrostatic force between the two charged spheres?
(A) $2.2 \times 10^{-2} \mathrm{~N}$
(B) $5.6 \times 10^{-2} \mathrm{~N}$
(C) $2.2 \times 10^{4} \mathrm{~N}$
(D) $5.6 \times 10^{4} \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 49

Which arrow best represents the direction of the resultant electric field at point $P$ due to the charges on spheres $A$ and $B$ ?(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 50

Two charged spheres are shown in the diagram.
Which polarities will produce the electric field shown?
(A) $A$ and $B$ both negative
(B) $A$ and $B$ both positive
(C) $A$ positive and $B$ negative
(D) $A$ negative and $B$ positive

Stephen Zaffke

Numerade Educator

Problem 51

If $1.0$ joule of work is required to move $1.0$ coulomb of charge between two points in an electric field, the potential difference between the two points is(A) $1.0 \times 10^{\circ} \mathrm{V}$
(B) $9.0 \times 10^{9} \mathrm{~V}$
(C) $6.3 \times 10^{18} \mathrm{~V}$
(D) $1.6 \times 10^{-19} \mathrm{~V}$

Stephen Zaffke

Numerade Educator

Problem 52

Which quantity of excess electric charge could be found on an object?
(A) $6.25 \times 10^{-19} \mathrm{C}$
(B) $4.80 \times 10^{-19} \mathrm{C}$
(C) $6.25$ elementary charges
(D) $1.60$ elementary charges

Stephen Zaffke

Numerade Educator

Problem 53

The diagram below represents two electrically charged identicalsized metal spheres, $A$ and $B$.

If the spheres are brought into contact, which sphere will have a net gain of electrons?(A) $A$, only
(B) $B$, only
(C) both $A$ and $B$
(D) neither $A$ nor $B$
Base your answers to questions 54 through 57 on the diagram below which shows a positive point charge placed at $A$.

Stephen Zaffke

Numerade Educator

Problem 54

The electric field intensity at point $B$ is $E$. At point $D$ the field intensity will be equal to
(A) $\frac{1}{9} E$
(B) $\frac{1}{9} E$
(C) $3 E$
(D) $9 E$

Stephen Zaffke

Numerade Educator

Problem 55

If a positive charge is placed at point $B$, the force exerted on this charge by charge $A$ will be directed toward
(A) the top of the page
(B) the bottom of the page
(C) $A$
(D) $C$

Stephen Zaffke

Numerade Educator

Problem 56

If the charge is moved from point $B$ to point $C$, the force between the two charges will
(A) decrease
(B) increase
(C) remain the same

Stephen Zaffke

Numerade Educator

Problem 57

The electric field surrounding charge $A$ is best represented by which diagram?(A)
(B)
(C)
(D)Base your answers to questions 58 through 62 on the diagram below which shows four point charges, $A, B, C$, and $D$, and three points, $X, Y$, and $Z$, in the electric field of these point charges.

Stephen Zaffke

Numerade Educator

Problem 58

Between which pair of charges is the electric force greatest?
(A) $A$ and $B$
(B) $A$ and $D$
(C) $B$ and $C$
(D) $B$ and $D$

Stephen Zaffke

Numerade Educator

Problem 59

The direction of the electric field of charge $A$ at point $X$ is
(A) upward
(B) downward
(C) toward charge $A$
(D) toward charge $B$

Stephen Zaffke

Numerade Educator

Problem 60

Compared to the intensity of the field of charge $A$ at point $X$, the intensity of the field of charge $A$ at point $Y$ is
(A) one-fourth as great
(B) the same
(C) twice as great
(D) 4 times as great

Stephen Zaffke

Numerade Educator

Problem 61

Compared to the intensity of the field of charge $A$ at point $X$, the intensity of the field of charge $B$ at point $X$ is
(A) one-fourth as great
(B) one-half as great
(C) the same
(D) twice as great

Stephen Zaffke

Numerade Educator

Problem 62

If the electric field intensity at point $Z$ is $1.0 \times 10^{5}$ newtons per coulomb, the force on a $2.0 \times 10^{-6}$ coulomb charge at point $Z$ will be
(A) $2.0 \times 10^{-1} \mathrm{~N}$
(B) $5.0 \times 10^{4} \mathrm{~N}$
(C) $2.0 \times 10^{5} \mathrm{~N}$
(D) $5.0 \times 10^{10} \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 63

The diagram below represents a positive test charge located near a positively charged sphere.

The greatest increase in the electric potential energy of the test charge relative to the sphere would be caused by moving the charge to point(A) $A$
(B) $B$
(C) $C$
(D) $D$

Stephen Zaffke

Numerade Educator

Problem 64

It takes 15 joules of work to bring $3.0$ coulombs of positive charge from infinity to a point. What is the electric potential at this point in an electric field?
(A) $45 . \mathrm{V}$
(B) $5.0 \mathrm{~V}$
(C) $0.20 \mathrm{~V}$
(D) $0 \mathrm{~V}$

Willis James

Numerade Educator

Problem 65

A positive test charge is moving between two oppositely charged plates. As the charge moves toward the negative plate, its potential energy
(A) decreases
(B) increases
(C) remains the same

Stephen Zaffke

Numerade Educator

Problem 66

A volt is defined as a
(A) joule/coulomb
(B) joule/second
(C) coulomb/second
(D) joule\cdotsecond/coulomb

Stephen Zaffke

Numerade Educator

Problem 67

The work required to move 2 coulombs of charge through a potential difference of 5 volts is
(A) $10 \mathrm{~J}$
(B) $2 \mathrm{~J}$
(C) $25 \mathrm{~J}$
(D) $50 \mathrm{~J}$

Stephen Zaffke

Numerade Educator

Problem 68

If $8.0$ joules of work is required to transfer $4.0$ coulombs of charge between two points, the potential difference between the two points is
(A) $6.4 \mathrm{~V}$
(B) $2.0 \mathrm{~V}$
(C) $32 \mathrm{~V}$
(D) 40. V

Stephen Zaffke

Numerade Educator

Problem 69

Two similar metal spheres, $A$ and $B$, have charges of $+2.0 \times 10^{-6}$ coulomb and $+1.0 \times 10^{-6}$ coulomb, respectively, as shown in the diagram below.
The magnitude of the electrostatic force on $A$ due to $B$ is $2.4$ newtons. What is the magnitude of the electrostatic force on $B$ due to $A$ ?(A) $1.2 \mathrm{~N}$
(B) $2.4 \mathrm{~N}$
(C) $4.8 \mathrm{~N}$
(D) $9.6 \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 70

If $1.6 \times 10^{-12}$ joule of energy is needed to move a charge through a potential difference of $1 \times 10^{7}$ volts then the magnitude of this charge is
(A) $1.6 \times 10^{-19} \mathrm{C}$
(B) $1.6 \times 10^{-5} \mathrm{C}$
(C) $1.6 \times 10^{5} \mathrm{C}$
(D) $1.6 \times 10^{19} \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 71

An electron-volt is a unit of
(A) potential difference
(B) charge
(C) current
(D) energy

Stephen Zaffke

Numerade Educator

Problem 72

an electron gains 2 electron-volts of energy as it is transferred from point $A$ to point $B$. The potential difference between points $A$ and $B$ is
(A) $3.2 \times 10^{-19} \mathrm{~V}$
(B) $2 \mathrm{~V}$
(C) $32 \mathrm{~V}$
(D) $1.25 \times 10^{19} \mathrm{~V}$

Stephen Zaffke

Numerade Educator

Problem 73

An energy of $13.6$ electron-volts is equivalent to(A) $1.60 \times 10^{-19} \mathrm{~J}$
(B) $2.18 \times 10^{-18} \mathrm{~J}$
(C) $6.25 \times 10^{-19} \mathrm{~J}$
(D) $6.63 \times 10^{-18} \mathrm{~J}$

Stephen Zaffke

Numerade Educator

Problem 74

Which quantity is equivalent to $3.2 \times 10^{-17}$ joule?
(A) $8.00 \times 10^{-3} \mathrm{eV}$
(B) $3.20 \times 10^{-17} \mathrm{eV}$
(C) $3.20 \mathrm{eV}$
(D) $200 \mathrm{eV}$

Stephen Zaffke

Numerade Educator

Problem 75

What is the maximum amount of kinetic energy that may be gained by a proton accelerated through a potential difference of 50 volts?
(A) $\mathrm{l} \mathrm{eV}$
(B) $10 \mathrm{eV}$
(C) $50 \mathrm{eV}$
(D) $100 \mathrm{eV}$
Base your answers to questions 76 through 78 on the diagram below. The diagram shows a negatively charged pith ball with a mass of $10^{-3}$ kilogram that is held suspended in the air by the
attractive force of a positively charged pith ball. The distance between the centers of the two pith balls is $0.01$ meter.

Stephen Zaffke

Numerade Educator

Problem 76

The minimum force needed to keep the negatively charged pith ball suspended in the air is approximately
(A) $10^{-5} \mathrm{~N}$
(B) $10^{-4} \mathrm{~N}$
(C) $10^{-3} \mathrm{~N}$
(D) $10^{-2} \mathrm{~N}$

Stephen Zaffke

Numerade Educator

Problem 77

The electrostatic field between the two pith balls is best represented by(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 78

If the magnitude of the charge on each pith ball is $1 \times 10^{-7}$ coulomb, the attractive force between them is
(A) $9 \times 10^{-3} \mathrm{~N}$
(B) $9 \times 10^{-2} \mathrm{~N}$
(C) $9 \times 10^{-1} \mathrm{~N}$
(D) $9.0 \mathrm{~N}$
Base your answers to questions 79 through 81 on the information below.

Stephen Zaffke

Numerade Educator

Problem 79

The magnitude of the electric field due to charge $+Q$ at distance $r$ is equal to
(A) $\frac{k Q}{\mathrm{~F}}$
(B) $\frac{k Q q}{r}$
(C) $\frac{Q}{r^{2}}$
(D) $\frac{k Q}{r^{2}}$

Stephen Zaffke

Numerade Educator

Problem 80

If 200 joules of work was required to move $+q$ through distance $r$ to $+Q$, the potential difference between the two charges would be
(A) $100 \mathrm{~V}$
(B) $200 \mathrm{~V}$
(C) $800 \mathrm{~V}$
(D) $50 \mathrm{~V}$

Stephen Zaffke

Numerade Educator

Problem 81

If distance $r$ is doubled, the force that $+Q$ exerts on $+q$ is(A) quartered
(B) halved
(C) unchanged
(D) doubled

Stephen Zaffke

Numerade Educator

Problem 82

If the distance separating an electron and a proton is halved, the magnitude of the electrostatic force between these charged particles will be
(A) unchanged
(B) doubled
(C) quartered
(D) quadrupled

Stephen Zaffke

Numerade Educator

Problem 83

In the diagram below, $P$ is a point near a negatively charged sphere.
Which vector best represents the direction of the electrical field at point $P$ ?(A)
(B) $\longrightarrow$
(C) $\mid$
(D)

Stephen Zaffke

Numerade Educator

Problem 84

Metal sphere $A$ has a charge of $-2$ units and an identical metal sphere, $B$, has a charge of $-4$ units. If the spheres are brought into contact with each other and then separated, the charge on sphere $B$ will be
(A) o units
(B) $-2$ units
(C) $-3$ units
(D) $+4$ units
Base your answers to questions 85 through 88 on the diagram below, which shows two identical metal spheres. Sphere $A$ has a charge of $+12$ coulombs, and sphere $B$ is a neutral sphere.

Stephen Zaffke

Numerade Educator

Problem 85

When spheres $A$ and $B$ come into contact, sphere $B$ will
(A) gain $6 \mathrm{C}$ of protons
(B) lose $6 \mathrm{C}$ of protons
(C) gain $6 \mathrm{C}$ of electrons
(D) lose $6 \mathrm{C}$ of electrons

Stephen Zaffke

Numerade Educator

Problem 86

When spheres $A$ and $B$ are in contact, the total charge of the system is
(A) neutral
(B) $+6 \mathrm{C}$
(C) $+12 \mathrm{C}$
$(\mathrm{D})+24 \mathrm{C}$

Stephen Zaffke

Numerade Educator

Problem 87

When spheres $A$ and $B$ are separated, the charge on sphere $A$ is
(A) $+12 \mathrm{C}$
(B) one-fourth of the original amount
(C) one-half of the original amount
(D) 4 times the original amount

Stephen Zaffke

Numerade Educator

Problem 88

After contact, the spheres are moved apart. As the distance between the spheres is increased, the electric potential energy of the system
(A) decreases
(B) increases
(C) remains the same
Base your answers to questions 89 through 93 on the diagram below, which shows three small metal spheres with different charges.

Stephen Zaffke

Numerade Educator

Problem 89

Which vector best represents the net force on sphere $B$ ?
(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 90

Compared to the force between spheres $A$ and $B$, the force between spheres $B$ and $C$ is
(A) one-quarter as great
(B) twice as great
(C) one-half as great
(D) 4 times as great

Stephen Zaffke

Numerade Educator

Problem 91

If sphere $A$ is moved further to the left, the magnitude of the net force on sphere $B$ will
(A) decrease
(B) increase
(C) remain the same

Stephen Zaffke

Numerade Educator

Problem 92

If the charge on sphere $B$ were decreased, the magnitude of the net force on sphere $B$ would
(A) decrease
(B) increase
(C) remain the same

Stephen Zaffke

Numerade Educator

Problem 93

If sphere $B$ were removed, the force of sphere $C$ on sphere $A$ would
(A) decrease
(B) increase
(C) remain the same
Base your answers to questions 94 through 98 on the diagram below, which represents two charged spheres, $X$ and $Y$.

Stephen Zaffke

Numerade Educator

Problem 94

At which point is the magnitude of the electric field equal to zero?
(A) $A$
(B) $B$
(C) $C$
(D) $D$

Stephen Zaffke

Numerade Educator

Problem 95

Which arrow best represents the direction of the electric field at point $A$ ?(A)
(B)
(C) |
(D)

Stephen Zaffke

Numerade Educator

Problem 96

If a unit positive charge moves directly from point $B$ to point $D$, the potential energy of the charge will
(A) decrease, only
(B) increase, only
(C) decrease, then increase
(D) increase, then decrease

Stephen Zaffke

Numerade Educator

Problem 97

Moving the two spheres toward each other would cause their electric potential energy to
(A) decrease
(B) increase
(C) remain the same

Stephen Zaffke

Numerade Educator

Problem 98

Compared to the force of the electric field of sphere $X$ on sphere $Y$, the force of the electric field of sphere $Y$ on sphere $X$ is
(A) less
(B) greater
(C) the same

Stephen Zaffke

Numerade Educator

Problem 99

Which graph best represents the relationship between the strength of an electric field and distance from a point charge?
(A)
(B)
(C)
(D)

Stephen Zaffke

Numerade Educator

Problem 100

An electron placed between oppositely charged parallel plates $A$ and $B$ moves toward plate $A$, as represented in the diagram below.
What is the direction of the electric field between the plates?(A) toward plate $A$
(B) toward plate $B$
(C) into the page
(D) out of the page

Stephen Zaffke

Numerade Educator