Question 1

Charge A and charge B are 3.12 m apart,and charge A is +1.49 C and charge B is +3.37 C.Charge C is located between them at a certain point and the force on charge C is zero.How far from charge A is charge C?
​

Accepted Answer

A)   1.87 m
B)   2.26 m
C)   1.25 m
D)   0.44 m
E)   2.07 mF) D) and E)
G) B) and E)

Question 2

A proton initially moves left to right long the x axis at a speed of 9 × 103 m/s.It moves into an electric field,which points in the negative x direction,and travels a distance of 0.8 m before coming to rest.If the proton's mass and charge are 1.67 × 10−27 kg and 1.60 × 10−19 C respectively,what is the magnitude of the electric field?
​

Accepted Answer

A)   42.8 N/C
B)   0.053 N/C
C)   0.528 N/C
D)   0.66 N/C
E)   1.057 N/CF) A) and B)
G) A) and C)

Question 3

If a conductor is in electrostatic equilibrium near an electrical charge:

Accepted Answer

A)   the total charge on the conductor must be zero.
B)   the electric field inside the conductor must be zero.
C)   any charges on the conductor must be uniformly distributed.
D)   the sum of all forces between the conductor and the charge must be zero.E) B) and C)
F) A) and D)

Question 4

An electron with a speed of 3 × 106 m/s moves into a uniform electric field of 600 N/C that is parallel to the electron's motion.How long does it take to bring the electron to rest? (me = 9.11 × 10−31 kg,e = 1.6 × 10−19 C)

Accepted Answer

A)   2.8 × 10−8 s
B)   0.9 × 10−8 s
C)   11.4 × 10−7 s
D)   2.6 × 10−6 s
E)   ​4.3 × 10−7 sF) A) and D)
G) B) and C)

Question 5

An initially uncharged hollow metallic sphere with radius of 6 cm has a small object with a charge of +19 µC carefully placed at the center of the sphere through a hole in the latter's surface.With the charge in place,what charge is now present on the outside surface of the sphere?
​

Accepted Answer

A)   zero
B)   −19 µC
C)   +7,600 µC
D)   +19 µC
E)   ​−7,600 µCF) A) and E)
G) B) and D)

Question 6

At what point is the charge per unit area greatest on the surface of an irregularly shaped conducting solid?

Accepted Answer

A)   where surface curves inward
B)   where surface is flat
C)   where curvature is least
D)   where curvature is greatestE) All of the above
F) B) and C)

Question 7

An electron is sent at high speed toward a gold nucleus (charge +79e) .What is the electrical force acting on the electron when it is 3.4 × 10−14 m away from the gold nucleus? (e = 1.6 × 10−19 C,ke = 8.99 × 109 N·m2/C2) 
​

Accepted Answer

A)   16 N
B)   1.57 N
C)   1.6 × 10−4 N
D)   1 × 10−6 N
E)   ​12.4F) A) and E)
G) A) and B)

Question 8

Two point charges are placed along a horizontal axis with the following values and positions: +3.6 µC at x = 0 cm and −7.1 µC at x = 40 cm.At what point along the x axis is the electric field zero?
​

Accepted Answer

A)   20 cm
B)   17 cm
C)   -10 cm
D)   -99 cm
E)   ​-139 cmF) A) and B)
G) D) and E)

Question 9

Two identical spheres each carry a charge of −47.1 µC.The spheres are separated by a distance of 1.74 m.What is the electric force between the spheres? (ke = 8.99 × 109 N·m2/C2) 
​

Accepted Answer

A)   0.1 N (repulsive) 
B)   6.6 N (repulsive) 
C)   11.5 N (attractive) 
D)   0.7 N (attractive) 
E)   ​13.2 N (attractive) F) D) and E)
G) C) and E)

Question 10

A charge,+Q,is placed inside a balloon and the balloon is inflated.As the radius of the balloon r increases the number of field lines going through the surface of the balloon:

Accepted Answer

A)   increases proportional to r2.
B)   increases proportional to r.
C)   stays the same.
D)   decreases as 1/r.E) B) and C)
F) All of the above

Question 11

Relative distribution of charge density on the surface of a conducting solid depends on:

Accepted Answer

A)   the shape of the conductor.
B)   mass density of the conductor.
C)   type of metal of which the conductor is made.
D)   strength of the earth's gravitational field.E) B) and D)
F) B) and C)

Question 12

Three equal positive charges are placed on the x-axis,one at the origin,one at x = 2 m,and the third at x = 6 m.Of the following points,which has the greatest magnitude electric field?
​

Accepted Answer

A)   x = 1 m
B)   x = 4 m
C)   x = 7 m
D)   The electric field has the same magnitude at all three positions.
E)   ​x = 0 mF) C) and D)
G) A) and B)

Question 13

An initially uncharged hollow metallic sphere with radius of 5 cm has a small object with a charge of +10 µC carefully placed at the center of the sphere through a hole in the latter's surface.What charge resides inner surface of the sphere?

Accepted Answer

A)   −4,000 µC
B)   -10 µC
C)   +10 µC
D)   zero
E)   ​+4,000F) A) and E)
G) B) and C)

Question 14

Two electrons are separated by 4 cm.What is the ratio of the electric force to the gravitational force between them? (me = 9.11 × 10−31 kg,ke = 8.99 × 109 N⋅m2/C2,G = 6.67 × 10-11 N⋅m2/kg2,and e = 1.6 × 10−19 C) 
​

Accepted Answer

A)   2.3 × 102
B)   1.3 × 1020
C)   3.1 × 1022
D)   4.2 × 1042
E)   1F) A) and C)
G) C) and D)

Question 15

The electric field associated with a uniformly charged hollow metallic sphere is the greatest at:

Accepted Answer

A)   the center of the sphere.
B)   the sphere's inner surface.
C)   infinity.
D)   the sphere's outer surface.E) B) and C)
F) A) and D)

Question 16

An airplane is flying through a thundercloud at a height of 2,500 m.(This is a very dangerous thing to do because of updrafts,turbulence,and the possibility of electric discharge. ) If there is a charge concentration of +31 C at height 4,000 m within the cloud and −31 C at height 500 m,what is the magnitude of the electric field E at the aircraft? (ke = 8.99 × 109 N·m2/C2)

Accepted Answer

A)   69,673 N/C
B)   123,862 N/C
C)   45,500 N/C
D)   193,535 N/C
E)   ​139,345 N/CF) All of the above
G) B) and D)

Question 17

Electric field is dimensionally equivalent to which of the following?

Accepted Answer

A)   N⋅m/C
B)   N/C
C)   N⋅m2/C2
D)   N/C2E) B) and C)
F) B) and D)

Question 18

In Millikan's oil drop experiment,if the electric field between the plates was of just the right magnitude,it would exactly balance the weight of the drop.Suppose a tiny spherical oil droplet of radius 1.3 × 10−4 cm carries a charge equivalent to one electron.What electric field is required to balance the weight? (The density of oil is 0.85 g/cm3,e = 1.6 × 10−19 C. ) 
​

Accepted Answer

A)   38.3 × 105 N/C
B)   0.6 × 105 N/C
C)   0 × 105 N/C
D)   4.8 × 105 N/C
E)   129.4 × 105 N/CF) A) and B)
G) C) and E)

Question 19

A metallic object holds a charge of −5.3 × 10−6 C.What total number of electrons does this represent? (e = 1.6 × 10−19 C is the magnitude of the electronic charge. )

Accepted Answer

A)   3.3 × 1014
B)   8.6 × 1013
C)   3.3 × 1013
D)   1.6 × 1014
E)   ​8.6 × 1014F) A) and E)
G) B) and C)

Question 20

The Millikan oil-drop experiment demonstrated that:

Accepted Answer

A)   small oil drops fall slowly through the air.
B)   light beams can be used to illuminate small oil droplets.
C)   the electronic charge is quantized.
D)   falling oil droplets reach terminal speed.E) B) and D)
F) C) and D)

Exam 15: Electric Forces and Electric Fields

Correct Answer
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Correct Answer
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Two electrons are separated by 4 cm.What is the ratio of the electric force to the gravitational force between them? (m_e = 9.11 × 10−³¹ kg,k_e = 8.99 × 10⁹ N⋅m²/C²,G = 6.67 × 10^-11 N⋅m²/kg²,and e = 1.6 × 10−¹⁹ C)

Correct Answer
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The Millikan oil-drop experiment demonstrated that:

Correct Answer
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Relative distribution of charge density on the surface of a conducting solid depends on:

Correct Answer
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An electron is sent at high speed toward a gold nucleus (charge +79e) .What is the electrical force acting on the electron when it is 3.4 × 10−¹⁴ m away from the gold nucleus? (e = 1.6 × 10−¹⁹ C,k_e = 8.99 × 10⁹ N·m²/C²)

Correct Answer
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A charge,+Q,is placed inside a balloon and the balloon is inflated.As the radius of the balloon r increases the number of field lines going through the surface of the balloon:

Correct Answer
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Three equal positive charges are placed on the x-axis,one at the origin,one at x = 2 m,and the third at x = 6 m.Of the following points,which has the greatest magnitude electric field?

Correct Answer
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An initially uncharged hollow metallic sphere with radius of 6 cm has a small object with a charge of +19 µC carefully placed at the center of the sphere through a hole in the latter's surface.With the charge in place,what charge is now present on the outside surface of the sphere?

Correct Answer
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An electron with a speed of 3 × 10⁶ m/s moves into a uniform electric field of 600 N/C that is parallel to the electron's motion.How long does it take to bring the electron to rest? (me = 9.11 × 10−³¹ kg,e = 1.6 × 10−¹⁹ C)

Correct Answer
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A metallic object holds a charge of −5.3 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

Correct Answer
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Electric field is dimensionally equivalent to which of the following?

Correct Answer
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At what point is the charge per unit area greatest on the surface of an irregularly shaped conducting solid?

Correct Answer
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The electric field associated with a uniformly charged hollow metallic sphere is the greatest at:

Correct Answer
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Correct Answer
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Two identical spheres each carry a charge of −47.1 µC.The spheres are separated by a distance of 1.74 m.What is the electric force between the spheres? (k_e = 8.99 × 10⁹ N·m²/C²)

Correct Answer
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Two point charges are placed along a horizontal axis with the following values and positions: +3.6 µC at x = 0 cm and −7.1 µC at x = 40 cm.At what point along the x axis is the electric field zero?

Correct Answer
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An initially uncharged hollow metallic sphere with radius of 5 cm has a small object with a charge of +10 µC carefully placed at the center of the sphere through a hole in the latter's surface.What charge resides inner surface of the sphere?

Correct Answer
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Charge A and charge B are 3.12 m apart,and charge A is +1.49 C and charge B is +3.37 C.Charge C is located between them at a certain point and the force on charge C is zero.How far from charge A is charge C?

Correct Answer
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If a conductor is in electrostatic equilibrium near an electrical charge:

Correct Answer
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Exam 15: Electric Forces and Electric Fields

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Two electrons are separated by 4 cm.What is the ratio of the electric force to the gravitational force between them? (me = 9.11 × 10−31 kg,ke = 8.99 × 109 N⋅m2/C2,G = 6.67 × 10-11 N⋅m2/kg2,and e = 1.6 × 10−19 C) ​

Correct AnswerverifiedShow Answer

The Millikan oil-drop experiment demonstrated that:

Correct AnswerverifiedShow Answer

Relative distribution of charge density on the surface of a conducting solid depends on:

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An electron is sent at high speed toward a gold nucleus (charge +79e) .What is the electrical force acting on the electron when it is 3.4 × 10−14 m away from the gold nucleus? (e = 1.6 × 10−19 C,ke = 8.99 × 109 N·m2/C2) ​

Correct AnswerverifiedShow Answer

A charge,+Q,is placed inside a balloon and the balloon is inflated.As the radius of the balloon r increases the number of field lines going through the surface of the balloon:

Correct AnswerverifiedShow Answer

Three equal positive charges are placed on the x-axis,one at the origin,one at x = 2 m,and the third at x = 6 m.Of the following points,which has the greatest magnitude electric field? ​

Correct AnswerverifiedShow Answer

An initially uncharged hollow metallic sphere with radius of 6 cm has a small object with a charge of +19 µC carefully placed at the center of the sphere through a hole in the latter's surface.With the charge in place,what charge is now present on the outside surface of the sphere? ​

Correct AnswerverifiedShow Answer

An electron with a speed of 3 × 106 m/s moves into a uniform electric field of 600 N/C that is parallel to the electron's motion.How long does it take to bring the electron to rest? (me = 9.11 × 10−31 kg,e = 1.6 × 10−19 C)

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A metallic object holds a charge of −5.3 × 10−6 C.What total number of electrons does this represent? (e = 1.6 × 10−19 C is the magnitude of the electronic charge. )

Correct AnswerverifiedShow Answer

Electric field is dimensionally equivalent to which of the following?

Correct AnswerverifiedShow Answer

At what point is the charge per unit area greatest on the surface of an irregularly shaped conducting solid?

Correct AnswerverifiedShow Answer

The electric field associated with a uniformly charged hollow metallic sphere is the greatest at:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Two identical spheres each carry a charge of −47.1 µC.The spheres are separated by a distance of 1.74 m.What is the electric force between the spheres? (ke = 8.99 × 109 N·m2/C2) ​

Correct AnswerverifiedShow Answer

Two point charges are placed along a horizontal axis with the following values and positions: +3.6 µC at x = 0 cm and −7.1 µC at x = 40 cm.At what point along the x axis is the electric field zero? ​

Correct AnswerverifiedShow Answer

An initially uncharged hollow metallic sphere with radius of 5 cm has a small object with a charge of +10 µC carefully placed at the center of the sphere through a hole in the latter's surface.What charge resides inner surface of the sphere?

Correct AnswerverifiedShow Answer

Charge A and charge B are 3.12 m apart,and charge A is +1.49 C and charge B is +3.37 C.Charge C is located between them at a certain point and the force on charge C is zero.How far from charge A is charge C? ​

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If a conductor is in electrostatic equilibrium near an electrical charge:

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Correct Answer
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Correct Answer
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Two electrons are separated by 4 cm.What is the ratio of the electric force to the gravitational force between them? (m_e = 9.11 × 10−³¹ kg,k_e = 8.99 × 10⁹ N⋅m²/C²,G = 6.67 × 10^-11 N⋅m²/kg²,and e = 1.6 × 10−¹⁹ C)

Correct Answer
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Correct Answer
verified

Correct Answer
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An electron is sent at high speed toward a gold nucleus (charge +79e) .What is the electrical force acting on the electron when it is 3.4 × 10−¹⁴ m away from the gold nucleus? (e = 1.6 × 10−¹⁹ C,k_e = 8.99 × 10⁹ N·m²/C²)

Correct Answer
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Correct Answer
verified

Three equal positive charges are placed on the x-axis,one at the origin,one at x = 2 m,and the third at x = 6 m.Of the following points,which has the greatest magnitude electric field?

Correct Answer
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An initially uncharged hollow metallic sphere with radius of 6 cm has a small object with a charge of +19 µC carefully placed at the center of the sphere through a hole in the latter's surface.With the charge in place,what charge is now present on the outside surface of the sphere?

Correct Answer
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An electron with a speed of 3 × 10⁶ m/s moves into a uniform electric field of 600 N/C that is parallel to the electron's motion.How long does it take to bring the electron to rest? (me = 9.11 × 10−³¹ kg,e = 1.6 × 10−¹⁹ C)

Correct Answer
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A metallic object holds a charge of −5.3 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
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Correct Answer
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Two identical spheres each carry a charge of −47.1 µC.The spheres are separated by a distance of 1.74 m.What is the electric force between the spheres? (k_e = 8.99 × 10⁹ N·m²/C²)

Correct Answer
verified

Two point charges are placed along a horizontal axis with the following values and positions: +3.6 µC at x = 0 cm and −7.1 µC at x = 40 cm.At what point along the x axis is the electric field zero?

Correct Answer
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Correct Answer
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Charge A and charge B are 3.12 m apart,and charge A is +1.49 C and charge B is +3.37 C.Charge C is located between them at a certain point and the force on charge C is zero.How far from charge A is charge C?

Correct Answer
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Correct Answer
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