Question 1

A hydrogen nucleus, which has a charge +e, is situated to the left of a carbon nucleus, which has a charge +6e. Which statement is true?

Accepted Answer

A) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is equal to the force exerted on the carbon nucleus. 
B) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is greater than the force exerted on the carbon nucleus. 
C) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is less than the force exerted on the carbon nucleus. 
D) The electrical force experienced by the hydrogen nucleus is to the right, and the magnitude is equal to the force exerted on the carbon nucleus. 
A) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is equal to the force exerted on the carbon nucleus. 
B) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is greater than the force exerted on the carbon nucleus. 
C) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is less than the force exerted on the carbon nucleus. 
D) The electrical force experienced by the hydrogen nucleus is to the right, and the magnitude is equal to the force exerted on the carbon nucleus. A

Question 2

The zirconium nucleus contains 40 protons, and an electron is 1.0 nm from the nucleus. What is the electric force on the electron due to the nucleus? ( e = 1.60 × 10-19 C, k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A) 2.9 nN 
B) 1000 C 
C) 3.7 nN 
D) 6.8 nN 
E) 9.2 nN 
A) 2.9 nN 
B) 1000 C 
C) 3.7 nN 
D) 6.8 nN 
E) 9.2 nN E

Question 3

If a charge generator builds a negative static charge of - $7.00 \mu \mathrm { C }$ how many electrons are transferred to it during this process. (e = 1.60 × 10-19 C

Accepted Answer

A) 4.38 × 1013 
B) 7.0 
C) 1.12 × 10-18 
D) 43.8 
A) 4.38 × 1013 
B) 7.0 
C) 1.12 × 10-18 
D) 43.8 A

Question 4

Two 10¢ coins (dimes)carrying identical charges are lying 2.5 m apart on a table. If each of these coins experiences an electrostatic force of magnitude 2.0 N due to the other coin, how large is the charge on each coin? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A) 2.6 μC 
B) 26 μC 
C) 6.7 μC 
D) 5.2 μC 
E) 52 μC 
A) 2.6 μC 
B) 26 μC 
C) 6.7 μC 
D) 5.2 μC 
E) 52 μC

Question 5

Two tiny particles having charges +20.0 ?C and -8.00 ?C are separated by a distance of 20.0 cm. What are the magnitude and direction of electric field midway between these two charges? (k = 1/4??0 = 9.0 × 109 N ? m2/C2)

Accepted Answer

A) 25.2 × $10 ^ { 6 }$ N/C directed towards the negative charge 
B) 25.2 × $10 ^ { 6 }$ N/C directed towards the positive charge 
C) 25.2 × $10 ^ { 5 }$ N/C directed towards the negative charge 
D) 25.2 × $10 ^ { 5 }$ N/C directed towards the positive charge 
E) 25.2 × $10 ^ { 4 }$ N/C directed towards the negative charge 
A) 25.2 × $10 ^ { 6 }$ N/C directed towards the negative charge 
B) 25.2 × $10 ^ { 6 }$ N/C directed towards the positive charge 
C) 25.2 × $10 ^ { 5 }$ N/C directed towards the negative charge 
D) 25.2 × $10 ^ { 5 }$ N/C directed towards the positive charge 
E) 25.2 × $10 ^ { 4 }$ N/C directed towards the negative charge

Question 6

A small styrofoam ball of mass 0.120 g is placed in an electric field of 6000 N/C pointing downward. What excess charge must be placed on the ball for it to remain suspended in the field?

Accepted Answer

A) -16.0 nC 
B) -18.0 nC 
C) -57.2 nC 
D) -125 nC 
E) -196 nC 
A) -16.0 nC 
B) -18.0 nC 
C) -57.2 nC 
D) -125 nC 
E) -196 nC

Question 7

Two point charges each experience a 1-N electrostatic force when they are 2 cm apart. If they are moved to a new separation of 8 cm, what is the magnitude of the electric force on each of them?

Accepted Answer

A) 2 N 
B) 1/2 N 
C) 1/4 N 
D) 1/8 N 
E) 1/16 N 
A) 2 N 
B) 1/2 N 
C) 1/4 N 
D) 1/8 N 
E) 1/16 N

Question 8

Electrically neutral objects cannot exert an electrical force on each other, but they can exert a gravitational force on each other.

Accepted Answer

A) True 
 B)False

Question 9

Three equal-magnitude point charges of varying signs 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) D 
A) A 
B) B 
C) C 
D) D

Question 10

Four tiny charged particles (two having a charge +Q and two having a charge -Q)are distributed on the x- and y-axes as shown in the figure. Each charge is equidistant from the origin. In which direction is the net electric field at the point P on the y-axis?

Accepted Answer

A) directly up (in the +y direction) 
B) directly left (-x direction) 
C) upwards and towards the left 
D) upwards and towards the right 
E) The net field is zero, so there is no direction. 
A) directly up (in the +y direction) 
B) directly left (-x direction) 
C) upwards and towards the left 
D) upwards and towards the right 
E) The net field is zero, so there is no direction.

Question 11

As shown in the figure, three small charges are equally spaced on the arc of a circle that is centered at the charge Q, where Q = +23 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 three charges? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A) 2.6 × 10-4 N 
B) 1.7 × 10-4 N 
C) 2.1 × 10-4 N 
D) 3.1 × 10-4 N 
A) 2.6 × 10-4 N 
B) 1.7 × 10-4 N 
C) 2.1 × 10-4 N 
D) 3.1 × 10-4 N

Question 12

Two parallel square metal plates, 8.4 cm on each side, are 2.5 mm apart and carry equal but opposite charge uniformly distributed over their facing surfaces. How much excess charge is there on each plate if the electric field between the plates has a magnitude of 2.0 × 106 N/C? (k = 1/4??0 = 8.99 × 109 N ? m2/C2)

Accepted Answer

Question 13

Two tiny beads are 25 cm apart with no other charges or fields present. Bead A carries 10 µC of charge and bead B carries 1 µC. Which one of the following statements is true about the magnitudes of the electric forces on these beads?

Accepted Answer

A) The force on A is 10 times the force on B. 
B) The force on B is 10 times the force on A. 
C) The force on A is exactly equal to the force on B. 
D) The force on A is 100 times the force on B. 
E) The force on B is 100 times the force on A. 
A) The force on A is 10 times the force on B. 
B) The force on B is 10 times the force on A. 
C) The force on A is exactly equal to the force on B. 
D) The force on A is 100 times the force on B. 
E) The force on B is 100 times the force on A.

Question 14

There is a +5.0-?C charge at three corners of a square having sides 70 mm long. What are the magnitude and direction of the net electrostatic force on +6.0 ?C placed at the center of the square? (k = 1/4??0 = 9.0 × 109 N ? m2/C2)

Accepted Answer

110 N towa

Question 15

A point charge Q1 = +6.0 nC is at the point (0.30 m, 0.00 m); a charge Q2 = -1.0 nC is at (0.00 m, 0.10 m), and a charge Q3 = +5.0 nC is at (0.00 m, 0.00 m). What are the magnitude and direction of the net force on the +5.0-nC charge due to the other two charges? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

5.4 µN at

Question 16

The electric field at a point 2.8 cm from a small object points toward the object with a strength of 180,000 N/C. What is the object's charge q? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A) -16 nC 
B) +16 nC 
C) -17 nC 
D) +17 nC 
A) -16 nC 
B) +16 nC 
C) -17 nC 
D) +17 nC

Question 17

Two very small plastic balls of equal mass are released from rest. One of them carries +10 µC of excess charge and the other one carries +1µC of charge. No other charges or fields are present. Which of the following statements are true about them as they move away from each other? (There may be more than one correct choice.)

Accepted Answer

A) The acceleration of the 10-µC ball is 10 times that of the 1-µC ball. 
B) The acceleration of the 1-µC ball is 10 times that of the 10-µC ball. 
C) The balls always have accelerations of equal magnitude. 
D) The speed of the balls keeps increasing. 
E) The acceleration of the balls keeps increasing. 
A) The acceleration of the 10-µC ball is 10 times that of the 1-µC ball. 
B) The acceleration of the 1-µC ball is 10 times that of the 10-µC ball. 
C) The balls always have accelerations of equal magnitude. 
D) The speed of the balls keeps increasing. 
E) The acceleration of the balls keeps increasing.

Question 18

If two objects are electrically attracted to each other,

Accepted Answer

A) both objects must be negatively charged. 
B) both objects must be positively charged. 
C) one object must be negatively charged and the other object must be positively charged. 
D) the objects could be electrically neutral. 
E) None of the above statements are absolutely true. 
A) both objects must be negatively charged. 
B) both objects must be positively charged. 
C) one object must be negatively charged and the other object must be positively charged. 
D) the objects could be electrically neutral. 
E) None of the above statements are absolutely true.

Question 19

Three point charges are located on the x-axis at the following positions: Q1 = +2.00 μC is at x = 1.00 m, Q2 = +3.00 μC is at x = 0.00, and Q3 = -5.00 μC is at x = -1.00 m. What is the magnitude of the electric force on Q2? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A) 0.0540 N 
B) 0.135 N 
C) 0.158 N 
D) 0.0810 N 
E) 0.189 N 
A) 0.0540 N 
B) 0.135 N 
C) 0.158 N 
D) 0.0810 N 
E) 0.189 N

Question 20

Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are doubled and their separation is also doubled, what happens to the electrical force that each charge exerts on the other one?

Accepted Answer

A) It increases by a factor of 2. 
B) It increases by a factor of $\sqrt { 2 }$ . 
C) It is reduced by a factor of $\sqrt { 2 }$ . 
D) It increases by a factor of 4. 
E) It remains the same. 
A) It increases by a factor of 2. 
B) It increases by a factor of $\sqrt { 2 }$ . 
C) It is reduced by a factor of $\sqrt { 2 }$ . 
D) It increases by a factor of 4. 
E) It remains the same.

Exam 20: Electric Fields and Forces

A hydrogen nucleus, which has a charge +e, is situated to the left of a carbon nucleus, which has a charge +6e. Which statement is true?

The zirconium nucleus contains 40 protons, and an electron is 1.0 nm from the nucleus. What is the electric force on the electron due to the nucleus? ( e = 1.60 × 10-19 C, k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

If a charge generator builds a negative static charge of - 7.00μC7.00 \mu \mathrm { C }7.00μC how many electrons are transferred to it during this process. (e = 1.60 × 10-19 C

Two 10¢ coins (dimes)carrying identical charges are lying 2.5 m apart on a table. If each of these coins experiences an electrostatic force of magnitude 2.0 N due to the other coin, how large is the charge on each coin? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Two tiny particles having charges +20.0 ?C and -8.00 ?C are separated by a distance of 20.0 cm. What are the magnitude and direction of electric field midway between these two charges? (k = 1/4??0 = 9.0 × 109 N ? m2/C2)

A small styrofoam ball of mass 0.120 g is placed in an electric field of 6000 N/C pointing downward. What excess charge must be placed on the ball for it to remain suspended in the field?

Two point charges each experience a 1-N electrostatic force when they are 2 cm apart. If they are moved to a new separation of 8 cm, what is the magnitude of the electric force on each of them?

Electrically neutral objects cannot exert an electrical force on each other, but they can exert a gravitational force on each other.

Three equal-magnitude point charges of varying signs 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?

Four tiny charged particles (two having a charge +Q and two having a charge -Q)are distributed on the x- and y-axes as shown in the figure. Each charge is equidistant from the origin. In which direction is the net electric field at the point P on the y-axis?

Two tiny beads are 25 cm apart with no other charges or fields present. Bead A carries 10 µC of charge and bead B carries 1 µC. Which one of the following statements is true about the magnitudes of the electric forces on these beads?

There is a +5.0-?C charge at three corners of a square having sides 70 mm long. What are the magnitude and direction of the net electrostatic force on +6.0 ?C placed at the center of the square? (k = 1/4??0 = 9.0 × 109 N ? m2/C2)

The electric field at a point 2.8 cm from a small object points toward the object with a strength of 180,000 N/C. What is the object's charge q? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

If two objects are electrically attracted to each other,

Three point charges are located on the x-axis at the following positions: Q1 = +2.00 μC is at x = 1.00 m, Q2 = +3.00 μC is at x = 0.00, and Q3 = -5.00 μC is at x = -1.00 m. What is the magnitude of the electric force on Q2? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are doubled and their separation is also doubled, what happens to the electrical force that each charge exerts on the other one?

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The zirconium nucleus contains 40 protons, and an electron is 1.0 nm from the nucleus. What is the electric force on the electron due to the nucleus? ( e = 1.60 × 10^-19 C, k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

If a charge generator builds a negative static charge of - $7.00 \mu \mathrm { C }$ how many electrons are transferred to it during this process. (e = 1.60 × 10^-1⁹ C

Two 10¢ coins (dimes)carrying identical charges are lying 2.5 m apart on a table. If each of these coins experiences an electrostatic force of magnitude 2.0 N due to the other coin, how large is the charge on each coin? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

Two tiny particles having charges +20.0 ?C and -8.00 ?C are separated by a distance of 20.0 cm. What are the magnitude and direction of electric field midway between these two charges? (k = 1/4??₀ = 9.0 × 10⁹ N ? m²/C²)

There is a +5.0-?C charge at three corners of a square having sides 70 mm long. What are the magnitude and direction of the net electrostatic force on +6.0 ?C placed at the center of the square? (k = 1/4??₀ = 9.0 × 10⁹ N ? m²/C²)

The electric field at a point 2.8 cm from a small object points toward the object with a strength of 180,000 N/C. What is the object's charge q? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Three point charges are located on the x-axis at the following positions: Q₁ = +2.00 μC is at x = 1.00 m, Q₂ = +3.00 μC is at x = 0.00, and Q₃ = -5.00 μC is at x = -1.00 m. What is the magnitude of the electric force on Q2? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Two point charges, Q₁ and Q₂, are separated by a distance R. If the magnitudes of both charges are doubled and their separation is also doubled, what happens to the electrical force that each charge exerts on the other one?