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Chapter 21: The Electric Field I: Discrete Charge Distributions . Section 21-1: Charge . Electric charges of the same sign . attract each other. repel each other. exert no forces on each other. . Electric charges of the same sign . attract each other. repel each other.

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chapter 21 the electric field i discrete charge distributions

Chapter 21: The Electric Field I: Discrete Charge Distributions

Section 21-1: Charge

electric charges of the same sign
Electric charges of the same sign
  • attract each other.
  • repel each other.
  • exert no forces on each other.
electric charges of the same sign3
Electric charges of the same sign
  • attract each other.
  • repel each other.
  • exert no forces on each other.
electric charges of the opposite sign
Electric charges of the opposite sign
  • attract each other.
  • exert no forces on each other.
  • repel each other.
electric charges of the opposite sign5
Electric charges of the opposite sign
  • attract each other.
  • exert no forces on each other.
  • repel each other.
electrons
Electrons
  • are about 2000 times more massive than protons.
  • are about 2000 times less massive than protons.
  • have about 2000 times more charge than protons.
  • have about 2000 times less charge than protons.
  • can have any amount of charge.
electrons7
Electrons
  • are about 2000 times more massive than protons.
  • are about 2000 times less massive than protons.
  • have about 2000 times more charge than protons.
  • have about 2000 times less charge than protons.
  • can have any amount of charge.
protons
Protons
  • are about 2000 times more massive than electrons.
  • are about 2000 times less massive than electrons.
  • have about 2000 times more charge than electrons.
  • have about 2000 times less charge than electrons.
  • can have any amount of charge.
protons9
Protons
  • are about 2000 times more massive than electrons.
  • are about 2000 times less massive than electrons.
  • have about 2000 times more charge than electrons.
  • have about 2000 times less charge than electrons.
  • can have any amount of charge.
experimental evidence indicates that
Experimental evidence indicates that
  • charge is quantized and conserved.
  • charge is quantized but not conserved.
  • charge is conserved but not quantized.
  • charge is neither quantized nor conserved.
experimental evidence indicates that11
Experimental evidence indicates that
  • charge is quantized and conserved.
  • charge is quantized but not conserved.
  • charge is conserved but not quantized.
  • charge is neither quantized nor conserved.
slide12

An electron (q = e) and a positron (q = e) can combine to give off two gamma rays. The net change in the algebraic sum of the charges before and after the combination is

  • +2e
  • zero
  • 2e
  • +e
  • e
slide13

An electron (q = e) and a positron (q = e) can combine to give off two gamma rays. The net change in the algebraic sum of the charges before and after the combination is

  • +2e
  • zero
  • 2e
  • +e
  • e
how many electrons must be transferred to a body to produce a charge of 125 nc
How many electrons must be transferred to a body to produce a charge of 125 nC?
  • 1.25 ´ 10–7
  • 1.60 ´ 10–19
  • 1.28 ´ 1012
  • 3.45 ´ 1011
  • 7.81 ´ 1011
how many electrons must be transferred to a body to produce a charge of 125 nc15
How many electrons must be transferred to a body to produce a charge of 125 nC?
  • 1.25 ´ 10–7
  • 1.60 ´ 10–19
  • 1.28 ´ 1012
  • 3.45 ´ 1011
  • 7.81 ´ 1011
slide16

A particular nucleus of the element erbium contains 68 protons and 90 neutrons. What is the total number of electrons in the neutral erbium atom?

  • 90
  • 158
  • 22
  • 68
  • None of the above
slide17

A particular nucleus of the element erbium contains 68 protons and 90 neutrons. What is the total number of electrons in the neutral erbium atom?

  • 90
  • 158
  • 22
  • 68
  • None of the above
chapter 21 the electric field i discrete charge distributions18

Chapter 21: The Electric Field I: Discrete Charge Distributions

Section 21-2: Conductors and Insulators and Concept Check 21-1a, 21-1b and 21-2

slide19

Two identical conducting spheres, one that has an initial charge +Q, the other initially uncharged, are brought into contact. What is the new charge on each sphere?

  • −Q
  • −Q/2
  • zero
  • +Q/2
  • +Q
slide20

Two identical conducting spheres, one that has an initial charge +Q, the other initially uncharged, are brought into contact. What is the new charge on each sphere?

  • −Q
  • −Q/2
  • zero
  • +Q/2
  • +Q
slide21

Two identical conducting spheres, one that has an initial charge +Q, the other initially uncharged, are brought into contact. While the spheres are in contact, a positively charged rod is moved close to one sphere, causing a redistribution of the charges on the two spheres so the charge on the sphere closest to the rod has a charge of −Q. What is the charge on the other sphere?

  • −2Q
  • −Q
  • zero
  • +Q
  • +2Q
slide22

Two identical conducting spheres, one that has an initial charge +Q, the other initially uncharged, are brought into contact. While the spheres are in contact, a positively charged rod is moved close to one sphere, causing a redistribution of the charges on the two spheres so the charge on the sphere closest to the rod has a charge of −Q. What is the charge on the other sphere?

  • −2Q
  • −Q
  • zero
  • +Q
  • +2Q
slide23

Two identical conducting spheres are charged by induction and then separated by a large distance; sphere 1 has charge +Q and sphere 2 has charge −Q. A third identical sphere is initially uncharged. If sphere 3 is touched to sphere 1 and separated, then touched to sphere 2 and separated, what is the final charge on each of the three spheres?

  • Q1 = +Q/4, Q2 = +Q/4, Q3 = −Q/2
  • Q1 = −Q/2, Q2 = +Q/4, Q3 = +Q/4
  • Q1 = +Q/2, Q2 = −Q/4, Q3 = −Q/4
  • Q1 = −Q/4, Q2 = −Q/2, Q3 = −Q/2
  • Q1 = −Q/2, Q2 = +Q/2, Q3 = +Q/2
slide24

Two identical conducting spheres are charged by induction and then separated by a large distance; sphere 1 has charge +Q and sphere 2 has charge −Q. A third identical sphere is initially uncharged. If sphere 3 is touched to sphere 1 and separated, then touched to sphere 2 and separated, what is the final charge on each of the three spheres?

  • Q1 = +Q/4, Q2 = +Q/4, Q3 = −Q/2
  • Q1 = −Q/2, Q2 = +Q/4, Q3 = +Q/4
  • Q1 = +Q/2, Q2 = −Q/4, Q3 = −Q/4
  • Q1 = −Q/4, Q2 = −Q/2, Q3 = −Q/2
  • Q1 = −Q/2, Q2 = +Q/2, Q3 = +Q/2
slide25

Two small spheres attract one another electrostatically. This can occur for a variety of reasons. Which of the following statements is true?

  • At least one sphere must be charged.
  • Neither sphere need be charged.
  • Both spheres must be charged and the charges must have the same sign.
  • Both spheres must be charged and the charges must have opposite signs.
slide26

Two small spheres attract one another electrostatically. This can occur for a variety of reasons. Which of the following statements is true?

  • At least one sphere must be charged.
  • Neither sphere need be charged.
  • Both spheres must be charged and the charges must have the same sign.
  • Both spheres must be charged and the charges must have opposite signs.
two small spheres repel one another electrostatically which of the following statements is true
Two small spheres repel one another electrostatically. Which of the following statements is true?
  • At least one sphere must be charged.
  • Neither sphere need be charged.
  • Both spheres must be charged and the charges must have the same sign.
  • Both spheres must be charged and the charges must have opposite signs.
two small spheres repel one another electrostatically which of the following statements is true28
Two small spheres repel one another electrostatically. Which of the following statements is true?
  • At least one sphere must be charged.
  • Neither sphere need be charged.
  • Both spheres must be charged and the charges must have the same sign.
  • Both spheres must be charged and the charges must have opposite signs.
slide29

If you bring a positively charged insulator near two uncharged metallic spheres that are in contact and then separate the spheres, the sphere on the right will have

  • no net charge.
  • a positive charge.
  • a negative charge.
slide30

If you bring a positively charged insulator near two uncharged metallic spheres that are in contact and then separate the spheres, the sphere on the right will have

  • no net charge.
  • a positive charge.
  • a negative charge.
slide31

If you bring a negatively charged insulator near two uncharged metallic spheres that are in contact and then separate the spheres, the sphere on the right will have

  • no net charge.
  • a positive charge.
  • a negative charge.
slide32

If you bring a negatively charged insulator near two uncharged metallic spheres that are in contact and then separate the spheres, the sphere on the right will have

  • no net charge.
  • a positive charge.
  • a negative charge.
slide33

A uniformly positively charged spherical conductor is placed midway between two identical uncharged conducting spheres. How would the charges in the middle sphere be distributed?

  • The positive charges stay uniformly distributed on the surface of the middle sphere.
  • There are more positive charges near the top and bottom of the sphere compared to the sides next to the two other spheres.
  • There are more positive charges near the sides of the spheres that are next to the other two spheres compared to the other regions of the sphere.
  • There are more positive charges near the front and back of the sphere compared to the sides next to the two other spheres.
  • None of these is correct.
slide34

A uniformly positively charged spherical conductor is placed midway between two identical uncharged conducting spheres. How would the charges in the middle sphere be distributed?

  • The positive charges stay uniformly distributed on the surface of the middle sphere.
  • There are more positive charges near the top and bottom of the sphere compared to the sides next to the two other spheres.
  • There are more positive charges near the sides of the spheres that are next to the other two spheres compared to the other regions of the sphere.
  • There are more positive charges near the front and back of the sphere compared to the sides next to the two other spheres.
  • None of these is correct.
chapter 21 the electric field i discrete charge distributions35

Chapter 21: The Electric Field I: Discrete Charge Distributions

Section 21-3: Coulomb’s Law

slide36

Two small spheres, each with mass m = 5.0 g and charge q, are suspended from a point by threads of length L = 0.30 m. What is the charge on each sphere if the threads make an angle theta of 20º with respect to the vertical?

  • 7.9 × 10–7 C
  • 2.9 × 10–7 C
  • 7.5 × 10–2 C
  • 6.3 × 10–13 C
  • 1.8 × 10–7 C
slide37

Two small spheres, each with mass m = 5.0 g and charge q, are suspended from a point by threads of length L = 0.30 m. What is the charge on each sphere if the threads make an angle theta of 20º with respect to the vertical?

  • 7.9 × 10–7 C
  • 2.9 × 10–7 C
  • 7.5 × 10–2 C
  • 6.3 × 10–13 C
  • 1.8 × 10–7 C
slide38

Three charges +q, +Q, and –Q are placed at the corners of an equilateral triangle as shown. The net force on charge +q due to the other two charges is

  • up.
  • down.
  • along a diagonal.
  • to the left.
  • to the right.
slide39

Three charges +q, +Q, and –Q are placed at the corners of an equilateral triangle as shown. The net force on charge +q due to the other two charges is

  • up.
  • down.
  • along a diagonal.
  • to the left.
  • to the right.
slide40

Charges q1 and q2 exert repulsive forces of 10 N on each other. What is the repulsive force when their separation is decreased so that their final separation is 80% of their initial separation?

  • 16 N
  • 12 N
  • 10 N
  • 8.0 N
  • 6.4 N
slide41

Charges q1 and q2 exert repulsive forces of 10 N on each other. What is the repulsive force when their separation is decreased so that their final separation is 80% of their initial separation?

  • 16 N
  • 12 N
  • 10 N
  • 8.0 N
  • 6.4 N
slide42

A proton is about 2000 times more massive that an electron but they both have charges of the same magnitude. The magnitude of the force on an electron by a proton is ____ the magnitude of the force on the proton by the electron.

  • greater than
  • equal to
  • less than
slide43

A proton is about 2000 times more massive that an electron but they both have charges of the same magnitude. The magnitude of the force on an electron by a proton is ____ the magnitude of the force on the proton by the electron.

  • greater than
  • equal to
  • less than
slide44

The Coulomb’s force between a proton and an electron is 2.271039 times greater than the gravitational force between them. If the two forces were equal, what should the size of the elementary charge be?

  • 1.60  10-19 C
  • 3.36  10-39 C
  • 1.23  10-77 C
  • 2.27  10-39 C
  • 4.41  10-40 C
slide45

The Coulomb’s force between a proton and an electron is 2.271039 times greater than the gravitational force between them. If the two forces were equal, what should the size of the elementary charge be?

  • 1.60  10-19 C
  • 3.36  10-39 C
  • 1.23  10-77 C
  • 2.27  10-39 C
  • 4.41  10-40 C
slide46

A charge 2Q is located at the origin while a second charge Q is located at x = a. Where should a third charge be placed so that the net force on this third charge is zero?

  • x < 0
  • 0 < x < a
  • x > a
  • x < 0 or 0 < x < a
  • 0 < x < a or x > a
slide47

A charge 2Q is located at the origin while a second charge Q is located at x = a. Where should a third charge be placed so that the net force on this third charge is zero?

  • x < 0
  • 0 < x < a
  • x > a
  • x < 0 or 0 < x < a
  • 0 < x < a or x > a
slide48

The force between two very small charged bodies is found to be F. If the distance between them is doubled without altering their charges, the force between them becomes

  • F/2
  • 2F
  • F/4
  • 4F
  • 1/F 2
slide49

The force between two very small charged bodies is found to be F. If the distance between them is doubled without altering their charges, the force between them becomes

  • F/2
  • 2F
  • F/4
  • 4F
  • 1/F 2
slide50

The force between two very small charged bodies is found to be F. If the distance between them is tripled without altering their charges, the force between them becomes

  • 9F
  • 3F
  • F/3
  • F/9
  • 1/F 3
slide51

The force between two very small charged bodies is found to be F. If the distance between them is tripled without altering their charges, the force between them becomes

  • 9F
  • 3F
  • F/3
  • F/9
  • 1/F 3
coulomb s law and newton s law of gravitation both involve which of the following
Coulomb's law and Newton's law of gravitation both involve which of the following?
  • the mass of the particle
  • the charge on the particle
  • permeability
  • permittivity
  • the inverse-square law
coulomb s law and newton s law of gravitation both involve which of the following53
Coulomb's law and Newton's law of gravitation both involve which of the following?
  • the mass of the particle
  • the charge on the particle
  • permeability
  • permittivity
  • the inverse-square law
which of the following statements is not true
Which of the following statements is not true?
  • In nature, electric charge is conserved.
  • The force of repulsion between two like charges is directly proportional to the product of the square of the charges.
  • The force of repulsion between two like charges is inversely proportional to the square of the distance separating the charges.
  • Unlike charges attract each other.
  • Like charges repel each other.
which of the following statements is not true55
Which of the following statements is not true?
  • In nature, electric charge is conserved.
  • The force of repulsion between two like charges is directly proportional to the product of the square of the charges.
  • The force of repulsion between two like charges is inversely proportional to the square of the distance separating the charges.
  • Unlike charges attract each other.
  • Like charges repel each other.
slide56

If a positive charge were placed at the origin (the crossing point of the vertical and horizontal lines) of the figure, into which quadrant would it feel a net force?

  • A
  • B
  • C
  • D
  • None, it feels no net force.
slide57

If a positive charge were placed at the origin (the crossing point of the vertical and horizontal lines) of the figure, into which quadrant would it feel a net force?

  • A
  • B
  • C
  • D
  • None, it feels no net force.
slide58

If a positive charge were placed at the origin (the crossing point of the vertical and horizontal lines) of the figure, into which quadrant would it feel a net force?

  • A
  • B
  • C
  • D
  • None, it feels no net force.
slide59

If a positive charge were placed at the origin (the crossing point of the vertical and horizontal lines) of the figure, into which quadrant would it feel a net force?

  • A
  • B
  • C
  • D
  • None, it feels no net force.
chapter 21 the electric field i discrete charge distributions60

Chapter 21: The Electric Field I: Discrete Charge Distributions

Section 21-4: The Electric Field

slide61
A proton is moving horizontally north in an electric field that points vertically upward. The electric force on the proton is
  • zero.
  • upward.
  • downward.
  • to the west.
  • to the east.
slide62
A proton is moving horizontally north in an electric field that points vertically upward. The electric force on the proton is
  • zero.
  • upward.
  • downward.
  • to the west.
  • to the east.
slide63
An electron is moving horizontally east in an electric field that points vertically upward. The electric force on the proton is
  • zero.
  • upward.
  • downward.
  • to the west.
  • to the east.
slide64
An electron is moving horizontally east in an electric field that points vertically upward. The electric force on the proton is
  • zero.
  • upward.
  • downward.
  • to the west.
  • to the east.
slide67

Two charges of the same sign are placed a certain distance apart. There is only one point in space near them where the electric field is zero. Which, if any, of the following statements about that point is true?

  • It cannot be on the line joining the charges.
  • It must be on the line joining the charges and between the charges.
  • It must be on the line joining the charges but not between the charges.
slide68

Two charges of the same sign are placed a certain distance apart. There is only one point in space near them where the electric field is zero. Which, if any, of the following statements about that point is true?

  • It cannot be on the line joining the charges.
  • It must be on the line joining the charges and between the charges.
  • It must be on the line joining the charges but not between the charges.
slide69

Three positive and equal charges Q1, Q2, and Q3 are at the corners of an equilateral triangle as shown. Point P is at the midpoint of the line between Q1 and Q3. The electric field at P is

  • zero.
  • not zero and is directed along the line from P to Q3.
  • not zero and is directed along the line from P to Q2.
  • not zero and is directed along the line from Q1 to Q2.
  • not zero and is directed along the line from P away from Q2.
slide70

Three positive and equal charges Q1, Q2, and Q3 are at the corners of an equilateral triangle as shown. Point P is at the midpoint of the line between Q1 and Q3. The electric field at P is

  • zero.
  • not zero and is directed along the line from P to Q3.
  • not zero and is directed along the line from P to Q2.
  • not zero and is directed along the line from Q1 to Q2.
  • not zero and is directed along the line from P away from Q2.
slide71

An electric field with a magnitude of 6.0 ´ 104 N/C is directed parallel to the positive y axis. A particle with a charge q = 4.8 ´ 10–19 C is moving along the x axis with a speed v = 3.0 ´ 106 m/s. The force on the charge is approximately

  • 8.6 ´ 10–8 N perpendicular to the xy plane.
  • 2.9 ´ 10–14 N in the +y direction.
  • 8.6 ´ 10–8 N in the +x direction.
  • zero.
  • 2.9 ´ 10–14 N in the +x direction.
slide72

An electric field with a magnitude of 6.0 ´ 104 N/C is directed parallel to the positive y axis. A particle with a charge q = 4.8 ´ 10–19 C is moving along the x axis with a speed v = 3.0 ´ 106 m/s. The force on the charge is approximately

  • 8.6 ´ 10–8 N perpendicular to the xy plane.
  • 2.9 ´ 10–14 N in the +y direction.
  • 8.6 ´ 10–8 N in the +x direction.
  • zero.
  • 2.9 ´ 10–14 N in the +x direction.
the direction of the electric field at a point is the same as
The direction of the electric field at a point is the same as
  • the direction of the force on a neutron placed at that point.
  • the direction of the force on a proton placed at that point.
  • the direction of the force on an electron placed at that point.
  • the direction of the force on a hydrogen molecule placed at that point.
  • None of these is correct.
the direction of the electric field at a point is the same as74
The direction of the electric field at a point is the same as
  • the direction of the force on a neutron placed at that point.
  • the direction of the force on a proton placed at that point.
  • the direction of the force on an electron placed at that point.
  • the direction of the force on a hydrogen molecule placed at that point.
  • None of these is correct.
slide75

Two point charges of unknown magnitude and sign are a distance d apart. If the electric field strength is zero at a point between them on the line joining them, you can conclude that

  • the charges are equal in magnitude but opposite in sign.
  • the charges are equal in magnitude and have the same sign.
  • the charges are not necessarily equal in magnitude but have opposite signs.
  • the charges are not necessarily equal in magnitude but have the same sign.
  • there is not enough information to say anything specific about the charges.
slide76

Two point charges of unknown magnitude and sign are a distance d apart. If the electric field strength is zero at a point between them on the line joining them, you can conclude that

  • the charges are equal in magnitude but opposite in sign.
  • the charges are equal in magnitude and have the same sign.
  • the charges are not necessarily equal in magnitude but have opposite signs.
  • the charges are not necessarily equal in magnitude but have the same sign.
  • there is not enough information to say anything specific about the charges.
slide77

Charges Q1 = –q and Q2 = +4q are placed as shown. At which of the five positions indicated by the lettered dots might the electric field be zero?

slide78

Charges Q1 = –q and Q2 = +4q are placed as shown. At which of the five positions indicated by the lettered dots might the electric field be zero?

in the diagram q 1 6 0 mc and q 2 6 0 mc the electric field at point 2 0 is
In the diagram, Q1 = 6.0 mC and Q2 = –6.0 mC. The electric field at point (2, 0) is
  • in the positive x direction.
  • in the negative x direction.
  • in the positive y direction.
  • in the negative y direction.
  • zero at this point.
in the diagram q 1 6 0 mc and q 2 6 0 mc the electric field at point 2 0 is80
In the diagram, Q1 = 6.0 mC and Q2 = –6.0 mC. The electric field at point (2, 0) is
  • in the positive x direction.
  • in the negative x direction.
  • in the positive y direction.
  • in the negative y direction.
  • zero at this point.
slide81

Two charges Q1 and Q2 are a distance d apart. If the electric field is zero at a distance of 3d/4 from Q1 (towards Q2), then what is the relation between Q1 and Q2?

  • Q1 = Q2 /9
  • Q1 = 9Q2
  • Q1 = Q2 /3
  • Q1 = 3Q2
  • Q1 = 4Q2 /3
slide82

Two charges Q1 and Q2 are a distance d apart. If the electric field is zero at a distance of 3d/4 from Q1 (towards Q2), then what is the relation between Q1 and Q2?

  • Q1 = Q2 /9
  • Q1 = 9Q2
  • Q1 = Q2 /3
  • Q1 = 3Q2
  • Q1 = 4Q2 /3
slide83

A conducting sphere with a net charge of q and mass m is suspended from the ceiling by a light string. A uniform electric field, E, is applied vertically downward on the sphere. The tension T in the string is ____ the weight mg.

  • less than
  • equal to
  • greater than
slide84

A conducting sphere with a net charge of q and mass m is suspended from the ceiling by a light string. A uniform electric field, E, is applied vertically downward on the sphere. The tension T in the string is ____ the weight mg.

  • less than
  • equal to
  • greater than
slide85

A conducting sphere with a net charge of q=−1 C and mass m = 1 g is suspended from the ceiling by a light string. A uniform electric field, E = 5000 N/C, is applied vertically downward on the sphere. The tension T in the string is

  • 5  10−3 N
  • 9.81  10−3 N
  • 4.81  10−3 N
  • 1.48  10−2 N
  • zero
slide86

A conducting sphere with a net charge of q=−1 C and mass m = 1 g is suspended from the ceiling by a light string. A uniform electric field, E = 5000 N/C, is applied vertically downward on the sphere. The tension T in the string is

  • 5  10−3 N
  • 9.81  10−3 N
  • 4.81  10−3 N
  • 1.48  10−2 N
  • zero
chapter 21 the electric field i discrete charge distributions87

Chapter 21: The Electric Field I: Discrete Charge Distributions

Section 21-5: Electric Field Lines

slide88

The point P is on the axis of a ring of charge, and all vectors shown lie in the yz plane. The negatively charged ring lies in the xz plane. The vector that correctly represents the direction of the electric field at this point is

slide89

The point P is on the axis of a ring of charge, and all vectors shown lie in the yz plane. The negatively charged ring lies in the xz plane. The vector that correctly represents the direction of the electric field at this point is

which of the following statements about electric field lines is not true
Which of the following statements about electric field lines is not true?
  • The number of lines leaving a positive charge or entering a negative charge is proportional to the charge.
  • The lines begin on positive charges and end on negative charges.
  • The density of the lines (the number per unit area perpendicular to the lines) is proportional to the magnitude of the field at that point.
  • Electric field lines cross midway between charges that have equal magnitude and sign.
  • The direction of each line indicates the direction that a positively charged particle would move if placed at that point in the electric field.
which of the following statements about electric field lines is not true91
Which of the following statements about electric field lines is not true?
  • The number of lines leaving a positive charge or entering a negative charge is proportional to the charge.
  • The lines begin on positive charges and end on negative charges.
  • The density of the lines (the number per unit area perpendicular to the lines) is proportional to the magnitude of the field at that point.
  • Electric field lines cross midway between charges that have equal magnitude and sign.
  • The direction of each line indicates the direction that a positively charged particle would move if placed at that point in the electric field.
slide92
The figure shows the field lines for two charges. What might be the ratio of the top charge to the bottom charge?
  • 1:2
  • 1:2
  • 2:1
  • 2:1
  • 2:1
slide93
The figure shows the field lines for two charges. What might be the ratio of the top charge to the bottom charge?
  • 1:2
  • 1:2
  • 2:1
  • 2:1
  • 2:1
slide94

A square has equal positive charges at three of its corners, as shown. Which arrow shows the correct direction of the electric field at point P?

slide95

A square has equal positive charges at three of its corners, as shown. Which arrow shows the correct direction of the electric field at point P?

slide96

A square has equal positive charges at three of its corners, as shown. Which arrow shows the correct direction of the electric field at point P?

slide97

A square has equal positive charges at three of its corners, as shown. Which arrow shows the correct direction of the electric field at point P?

slide98

In the figure, the direction of the electric field at a point equidistant from two charged bodies A and B is indicated by a vector. Both charges have the same magnitude. The direction of the vector indicates that

  • both A and B are positive.
  • both A and B are negative.
  • A is positive and B is negative.
  • B is positive and A is negative.
  • B is negative and A is neutral.
slide99

In the figure, the direction of the electric field at a point equidistant from two charged bodies A and B is indicated by a vector. Both charges have the same magnitude. The direction of the vector indicates that

  • both A and B are positive.
  • both A and B are negative.
  • A is positive and B is negative.
  • B is positive and A is negative.
  • B is negative and A is neutral.
chapter 21 the electric field i discrete charge distributions100

Chapter 21: The Electric Field I: Discrete Charge Distributions

Section 21-6: Action of the Electric Field on Charges

if nonelectric forces are negligible in a uniform electric field a proton has
If nonelectric forces are negligible, in a uniform electric field a proton has
  • a constant velocity in the direction of the field.
  • a constant velocity in a direction opposite to that of the field.
  • a constant acceleration the direction of the field.
  • a constant acceleration in a direction opposite to that of the field.
  • a constant acceleration in a direction at right angles to the field.
if nonelectric forces are negligible in a uniform electric field a proton has102
If nonelectric forces are negligible, in a uniform electric field a proton has
  • a constant velocity in the direction of the field.
  • a constant velocity in a direction opposite to that of the field.
  • a constant acceleration the direction of the field.
  • a constant acceleration in a direction opposite to that of the field.
  • a constant acceleration in a direction at right angles to the field.
slide103
If nonelectric forces are negligible, a positively charged particle released from rest in a nonuniform electric field
  • moves perpendicular to the field with constant velocity.
  • moves with constant velocity parallel to the field.
  • accelerates in the direction of the field.
  • accelerates perpendicularly to the field.
  • moves only along equipotential lines.
slide104
If nonelectric forces are negligible, a positively charged particle released from rest in a nonuniform electric field
  • moves perpendicular to the field with constant velocity.
  • moves with constant velocity parallel to the field.
  • accelerates in the direction of the field.
  • accelerates perpendicularly to the field.
  • moves only along equipotential lines.
slide105

A negatively charged particle moving with speed v enters a region of uniform electric field E. Using the direction compass on the right, the direction of the force on the charge is

  • 1
  • 2
  • 3
  • 4
  • There is no force on the charge.
slide106

A negatively charged particle moving with speed v enters a region of uniform electric field E. Using the direction compass on the right, the direction of the force on the charge is

  • 1
  • 2
  • 3
  • 4
  • There is no force on the charge.
slide107

A negatively charged particle moving with speed v enters a region of uniform electric field E. If the charge q = 1 nC, mass m = 1 × 1014 kg, speed v = 105 m/s, the electric field strength E = 2 × 105 V/m, and width, w, of the electric field is 0.2 m, what is the speed of the particle when it emerges from the other side?

  • 1.0 × 105 m/s
  • 4.0 × 104 m/s
  • 1.08 × 105 m/s
  • 1.4 × 105 m/s
  • 1.8 × 105 m/s
slide108

A negatively charged particle moving with speed v enters a region of uniform electric field E. If the charge q = 1 nC, mass m = 1 × 1014 kg, speed v = 105 m/s, the electric field strength E = 2 × 105 V/m, and width, w, of the electric field is 0.2 m, what is the speed of the particle when it emerges from the other side?

  • 1.0 × 105 m/s
  • 4.0 × 104 m/s
  • 1.08 × 105 m/s
  • 1.4 × 105 m/s
  • 1.8 × 105 m/s
slide109

An electric dipole consists of a positive charge separated from a negative charge of the same magnitude by a small distance. Which, if any, of the diagrams best represents the electric field lines around an electric dipole?

  • 1
  • 2
  • 3
  • 4
  • None of these is correct.
slide110

An electric dipole consists of a positive charge separated from a negative charge of the same magnitude by a small distance. Which, if any, of the diagrams best represents the electric field lines around an electric dipole?

  • 1
  • 2
  • 3
  • 4
  • None of these is correct.
slide111

Two electric dipoles, p1 and p2, are arranged as shown. The first dipole is not free to rotate but the second dipole can rotate in any direction. Which way will p2 rotate? The directions represent the following: 1 – clockwise, 2 – counter-clockwise, 3 – rotate about axis of the dipole rolling up, and 4 – rotate about axis of the dipole rolling down.

  • 1
  • 2
  • 3
  • 4
  • None of these is correct.
slide112

Two electric dipoles, p1 and p2, are arranged as shown. The first dipole is not free to rotate but the second dipole can rotate in any direction. Which way will p2 rotate? The directions represent the following: 1 – clockwise, 2 – counter-clockwise, 3 – rotate about axis of the dipole rolling up, and 4 – rotate about axis of the dipole rolling down.

  • 1
  • 2
  • 3
  • 4
  • None of these is correct.
slide113

An electric dipole of momentp is placed in a uniform external electric field. The dipole moment vectorp is in the positive y direction. The external electric field vector E is in the positive x direction. When the dipole is aligned as shown in the diagram, the net torque is in the

  • positive x direction.
  • positive y direction.
  • negative x direction.
  • positive z direction.
  • negative z direction.
slide114

An electric dipole of momentp is placed in a uniform external electric field. The dipole moment vectorp is in the positive y direction. The external electric field vector E is in the positive x direction. When the dipole is aligned as shown in the diagram, the net torque is in the

  • positive x direction.
  • positive y direction.
  • negative x direction.
  • positive z direction.
  • negative z direction.