Question 1

As shown in the figure, three charges are at the vertices of an equilateral triangle. The charge Q is 6.7 nC, and all the other quantities are accurate to two significant figures. What is the magnitude of the net electric force on the charge Q due to the other two charges? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)  0 = 9.0 × 109 N ∙ m2/C2)    A) 2.1 × 10-3 N B) 1.2 × 10-3 N C) 1.0 × 10-3 N D) 1.4 × 10-3 N" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  2.1 × 10-3 N
B)  1.2 × 10-3 N
C)  1.0 × 10-3 N
D)  1.4 × 10-3 NE) B) and D)
F) All of the above

Question 2

An electron is placed in a uniform electric field of 4.5 × 104 N/C that points to the right. (e = 1.6 × 10-19 C, melectron = 9.11 × 10-31 kg)
(a)What are the magnitude and direction of the force on the electron?
(b)If the electron is released from rest, what is its speed after 3.0 ps?

Accepted Answer

(a)7.2 × 1...

Question 3

The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long threads. The spheres repel each other after each one is given the same positive charge and hang at rest when θ = 4.1°. What is the charge on each sphere? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)  0 = 9.0 × 109 N ∙ m2/C2)    A) 22 nC B) 89 nC C) 360 nC D) 180 nC E) 45 nC" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  22 nC
B)  89 nC
C)  360 nC
D)  180 nC
E)  45 nCF) A) and C)
G) A) and E)

Question 4

The figure shows electric field lines arising from two small charged particles P and Q. Consider the following two statements: (i) The charge on P is smaller than the charge on Q.
(ii) The electrostatic force on P is smaller than the force on Q.
Which of the above statements are true?

Accepted Answer

A)  Only (i) is true.
B)  Only (ii) is true.
C)  Both (i) and (ii) are true.
D)  Neither (i) nor (ii) is true.E) B) and D)
F) B) and C)

Question 5

An electron is projected with an initial velocity v0 = 8.4 ×  10710 ^ { 7 }107  m/s along the y-axis, which is the centerline between a pair of charged plates, as shown in the figure. The plates are 1.0 m long and are separated by 0.10 m. A uniform electric field of magnitude E in the +x-direction is present between the plates. If the magnitude of the acceleration of the electron is measured to be  8.9×1015 m/s28.9 	imes 10 ^ { 15 } \mathrm {~m} / \mathrm { s } ^ { 2 }8.9×1015 m/s2  what is the magnitude of the electric field between the plates? (e = 1.6 × 10-19 C, melectron = 9.11 × 10-31 kg)  0 = 8.4 ×  10 ^ { 7 }  m/s along the y-axis, which is the centerline between a pair of charged plates, as shown in the figure. The plates are 1.0 m long and are separated by 0.10 m. A uniform electric field of magnitude E in the +x-direction is present between the plates. If the magnitude of the acceleration of the electron is measured to be  8.9 	imes 10 ^ { 15 } \mathrm {~m} / \mathrm { s } ^ { 2 }  what is the magnitude of the electric field between the plates? (e = 1.6 × 10-19 C, melectron = 9.11 × 10-31 kg)    A) 51,000 N/C B) 45,000 N/C C) 40,000 N/C D) 35,000 N/C E) 29,000 N/C " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  51,000 N/C
B)  45,000 N/C
C)  40,000 N/C
D)  35,000 N/C
E)  29,000 N/C F) D) and E)
G) All of the above

Question 6

When 1.0-µC point charge is 15 m from a second point charge, the force each one experiences a force of 1.0 µN. What is the magnitude of the second charge? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A)  25 C
B)  1.0 C
C)  10 nC
D)  0.025 C
E)  25 nCF) B) and E)
G) None of the above

Question 7

Two tiny particles having charges of +7.00 μC and -9.00 μC are placed along the y-axis. The +7.00-µC particle is at y = 0.00 cm, and the other particle is at y = 40.00 cm. Where must a third charged particle be placed along the y-axis so that it does not experience any net electric force due to the other two particles?

Accepted Answer

A)  0.200 m
B)  2.99 m
C)  -0.187 m
D)  -2.99 m
E)  0.187 mF) C) and D)
G) A) and D)

Question 8

One point charge +Q is placed at the center of a square, and a second point charge -Q is placed at the upper-left corner of the square. It is observed that an electrostatic force of magnitude 2.0 N acts on the positive charge at the center. Now a third charge -Q is placed at the lower-left corner of the square, as shown in the figure. What is the magnitude of the net force that acts on the center charge now?

Accepted Answer

A)  0.0 N
B)  2.8 N
C)  4.0 N
D)  5.3 NE) B) and D)
F) A) and B)

Question 9

As shown in the figure, three charges are at corners of a rectangle. The charge in the bottom right corner is Q = - 90 nC, and all the other quantities are accurate to two significant figures. What is the magnitude of the net electrical force on Q due to the other two charges? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)  0 = 9.0 × 109 N ∙ m2/C2)    A) 3.8 × 10-2 N B) 2.8 × 10-2 N C) 5.3 × 10-2 N D) 7.1 × 10-2 N" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  3.8 × 10-2 N
B)  2.8 × 10-2 N
C)  5.3 × 10-2 N
D)  7.1 × 10-2 NE) A) and B)
F) A) and C)

Question 10

A small glass bead has been charged to 1.9 nC. What is the strength of the electric field 2.0 cm from the center of the bead? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A)  4.3 × 104 N/C
B)  8.5 × 102 N/C
C)  8.1 × 10-5 N/C
D)  8.5 × 10-7 N/CE) B) and D)
F) None of the above

Question 11

Three equal positive point charges +q are placed at the corners of a square of side d as shown in the figure. Which one of the arrows shown represents the direction of the net electric field at the center of the square?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) None of the above
F) A) and D)

Question 12

A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod

Accepted Answer

A)  is repelled by the sphere.
B)  is attracted to the sphere.
C)  feels no force due to the sphere.D) All of the above
E) B) and C)

Question 13

(a)

(b) 
 X and Y are two initially uncharged metal spheres on insulating stands, and they are in contact with each other. A positively charged rod R is brought close to X as shown in part (a) of the figure. Sphere Y is now moved away from X, as shown in part (b) . What are the final charge states of X and Y?

Accepted Answer

A)  Both X and Y are neutral.
B)  X is positive and Y is neutral.
C)  X is neutral and Y is positive.
D)  X is negative and Y is positive.
E)  Both X and Y are negative.F) A) and D)
G) D) and E)

Question 14

A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?

Accepted Answer

A)  The sphere near the charged rod becomes positive and the other one becomes negative.
B)  The sphere near the charged rod becomes negative and the other one becomes positive.
C)  The spheres do not get any charge.
D)  Both spheres become negative.
E)  Both spheres become positive.F) C) and D)
G) A) and E)

Question 15

A +5.0-μC point charge is placed at the 0 cm mark of a meter stick and a -4.0-μC charge is placed at the 50 cm mark. What is the net electric field at the 30 cm mark? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A)  4.0 × 105 N/C
B)  5.0 × 105 N/C
C)  9.0 × 105 N/C
D)  1.4 × 106 N/CE) A) and B)
F) A) and C)

Question 16

Four point charges Q of equal magnitude and sign are arranged on three of the corners of the square of side d as shown in the figure Which one of the arrows shown represents the net force acting on the charge at the upper right hand corner of the square?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) A) and B)
F) A) and D)

Question 17

A small object with a 5.0-μC charge is accelerating horizontally on a friction-free surface at 0.0050 m/s2 due only to an electric field. If the object has a mass of 2.0 g, what is the magnitude of the electric field?

Accepted Answer

A)  2.0 N/C
B)  4.0 N/C
C)  0.0020 N/C
D)  0.0040 N/C
E)  1.0 N/CF) All of the above
G) None of the above

Question 18

An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction, with no other forces present. Which of the following statements are true just before they are about to collide? (There could be more than one correct choice.)

Accepted Answer

A)  They are closer to the to the initial position of the electron that to the initial position of the proton.
B)  They are closer to the to the initial position of the proton that to the initial position of the electron.
C)  They are at the midpoint of their initial separation.
D)  They both have the same speed.
E)  The electrostatic force on the proton is greater than the electrostatic force on the electron.F) None of the above
G) B) and E)

Question 19

A small charged plastic ball is vertically above another charged small ball in a frictionless test tube as shown in the figure. The balls are in equilibrium a distance d apart. If the charge on each ball is doubled, the equilibrium distance between the balls in the test tube would become

Accepted Answer

A)    2\sqrt { 2 }2c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​  d.
B)  2d.
C)  4d.
D)  8d.
E)  d/4. F) A) and C)
G) C) and D)

Question 20

A small 0.050-kg insulating sphere carries a charge of -60 μC and is hanging by a vertical silk thread from a fixed point in the ceiling. An external uniform vertical electric field is now applied. If the applied electric field has a magnitude of 3000 N/C and is directed downward, what is the tension in the silk thread? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A)  0.19 N
B)  0.31 N
C)  0.41 N
D)  0.52 N
E)  0.71 NF) B) and E)
G) A) and C)

Exam 20: Electric Fields and Forces

Correct Answer
verified

A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

A small object with a 5.0-μC charge is accelerating horizontally on a friction-free surface at 0.0050 m/s2 due only to an electric field. If the object has a mass of 2.0 g, what is the magnitude of the electric field?

Correct Answer
verified

Correct Answer
verified

A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod

Correct Answer
verified

When 1.0-µC point charge is 15 m from a second point charge, the force each one experiences a force of 1.0 µN. What is the magnitude of the second charge? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

The figure shows electric field lines arising from two small charged particles P and Q. Consider the following two statements: (i) The charge on P is smaller than the charge on Q. (ii) The electrostatic force on P is smaller than the force on Q. Which of the above statements are true?

Correct Answer
verified

Correct Answer
verified

The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long threads. The spheres repel each other after each one is given the same positive charge and hang at rest when θ = 4.1°. What is the charge on each sphere? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

A +5.0-μC point charge is placed at the 0 cm mark of a meter stick and a -4.0-μC charge is placed at the 50 cm mark. What is the net electric field at the 30 cm mark? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction, with no other forces present. Which of the following statements are true just before they are about to collide? (There could be more than one correct choice.)

Correct Answer
verified

An electron is placed in a uniform electric field of 4.5 × 104 N/C that points to the right. (e = 1.6 × 10^-19 C, m_electron = 9.11 × 10-31 kg) (a)What are the magnitude and direction of the force on the electron? (b)If the electron is released from rest, what is its speed after 3.0 ps?

Correct Answer
verified
(a)7.2 × 1...
View Answer

Three equal positive point charges +q are placed at the corners of a square of side d as shown in the figure. Which one of the arrows shown represents the direction of the net electric field at the center of the square?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Four point charges Q of equal magnitude and sign are arranged on three of the corners of the square of side d as shown in the figure Which one of the arrows shown represents the net force acting on the charge at the upper right hand corner of the square?

Correct Answer
verified

A small glass bead has been charged to 1.9 nC. What is the strength of the electric field 2.0 cm from the center of the bead? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

Exam 20: Electric Fields and Forces

A small charged plastic ball is vertically above another charged small ball in a frictionless test tube as shown in the figure. The balls are in equilibrium a distance d apart. If the charge on each ball is doubled, the equilibrium distance between the balls in the test tube would become

Correct AnswerverifiedShow Answer

A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A small object with a 5.0-μC charge is accelerating horizontally on a friction-free surface at 0.0050 m/s2 due only to an electric field. If the object has a mass of 2.0 g, what is the magnitude of the electric field?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod

Correct AnswerverifiedShow Answer

When 1.0-µC point charge is 15 m from a second point charge, the force each one experiences a force of 1.0 µN. What is the magnitude of the second charge? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Correct AnswerverifiedShow Answer

The figure shows electric field lines arising from two small charged particles P and Q. Consider the following two statements: (i) The charge on P is smaller than the charge on Q. (ii) The electrostatic force on P is smaller than the force on Q. Which of the above statements are true?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long threads. The spheres repel each other after each one is given the same positive charge and hang at rest when θ = 4.1°. What is the charge on each sphere? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Correct AnswerverifiedShow Answer

A +5.0-μC point charge is placed at the 0 cm mark of a meter stick and a -4.0-μC charge is placed at the 50 cm mark. What is the net electric field at the 30 cm mark? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Correct AnswerverifiedShow Answer

An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction, with no other forces present. Which of the following statements are true just before they are about to collide? (There could be more than one correct choice.)

Correct AnswerverifiedShow Answer

An electron is placed in a uniform electric field of 4.5 × 104 N/C that points to the right. (e = 1.6 × 10-19 C, melectron = 9.11 × 10-31 kg) (a)What are the magnitude and direction of the force on the electron? (b)If the electron is released from rest, what is its speed after 3.0 ps?

Correct Answerverified(a)7.2 × 1...View AnswerShow Answer

Three equal positive point charges +q are placed at the corners of a square of side d as shown in the figure. Which one of the arrows shown represents the direction of the net electric field at the center of the square?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Four point charges Q of equal magnitude and sign are arranged on three of the corners of the square of side d as shown in the figure Which one of the arrows shown represents the net force acting on the charge at the upper right hand corner of the square?

Correct AnswerverifiedShow Answer

A small glass bead has been charged to 1.9 nC. What is the strength of the electric field 2.0 cm from the center of the bead? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

When 1.0-µC point charge is 15 m from a second point charge, the force each one experiences a force of 1.0 µN. What is the magnitude of the second charge? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long threads. The spheres repel each other after each one is given the same positive charge and hang at rest when θ = 4.1°. What is the charge on each sphere? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

A +5.0-μC point charge is placed at the 0 cm mark of a meter stick and a -4.0-μC charge is placed at the 50 cm mark. What is the net electric field at the 30 cm mark? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Correct Answer
verified

Correct Answer
verified

An electron is placed in a uniform electric field of 4.5 × 104 N/C that points to the right. (e = 1.6 × 10^-19 C, m_electron = 9.11 × 10-31 kg) (a)What are the magnitude and direction of the force on the electron? (b)If the electron is released from rest, what is its speed after 3.0 ps?

Correct Answer
verified
(a)7.2 × 1...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

A small glass bead has been charged to 1.9 nC. What is the strength of the electric field 2.0 cm from the center of the bead? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Correct Answer
verified