Question 1

Which one of the following statements concerning electrostatic situations is false?

Accepted Answer

A) E is zero everywhere inside a conductor. 
B) Equipotential surfaces are always perpendicular to E. 
C) Zero work is needed to move a charge along an equipotential surface. 
D) If V is constant throughout a region of space, then E must be zero in that region. 
E) No force component acts along the path of a charge as it is moved along an equipotential surface.

Question 2

The magnitude of the charge on the plates of an isolated parallel plate capacitor is doubled. Which one of the following statements is true concerning the capacitance of this parallel-plate system?

Accepted Answer

A) The capacitance is decreased to one half of its original value. 
B) The capacitance is increased to twice its original value. 
C) The capacitance remains unchanged. 
D) The capacitance depends on the electric field between the plates. 
E) The capacitance depends on the potential difference across the plates.

Question 3

Complete the following statement: The electron volt is a unit of

Accepted Answer

A) energy. 
B) electric field strength. 
C) electric force. 
D) electric potential difference. 
E) electric power.

Question 4

The sketch below shows cross sections of equipotential surfaces between two charged conductors that are shown in solid grey. Various points on the equipotential surfaces near the conductors are labeled A, B, C, ..., I. 
-A point charge gains 50 $\mu$J of electric potential energy when it is moved from point D to point G. Determine the magnitude of the charge.

Accepted Answer

A) 1.0 $\mu$C 
B) 1.3 $\mu$C 
C) 25 $\mu$C 
D) 50$\mu$C 
E) 130 $\mu$C

Question 5

Which one of the following statements is true concerning the work done by an external force in moving an electron at constant speed between two points in an electrostatic field?

Accepted Answer

A) The work done is always zero joules. 
B) The work done is always positive. 
C) The work done only depends on the speed of the electron. 
D) The work done depends on the total distance covered. 
E) The work done depends only on the displacement of the electron.

Question 6

Three point charges -Q, -Q, and +3Q are arranged along a line as shown in the sketch.  What is the electric potential at the point P?

Accepted Answer

A) +kQ/R 
B) -2kQ/R 
C) -1.6kQ/R 
D) +1.6kQ/R 
E) +4.4kQ/R

Question 7

P and Q are points within a uniform electric field that are separated by a distance of 0.2 m as shown. The potential difference between P and Q is 75 V. 
-Determine the magnitude of this electric field.

Accepted Answer

A) 15 V/m 
B) 75 V/m 
C) 375 V/m 
D) 750 V/m 
E) 1100 V/m

Question 8

Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. 
-What is the magnitude of the electric field at P, the center of the square?

Accepted Answer

A) kQ/a2 
B) 2kQ/a2 
C) 4kQ/a2 
D) kQ/4a2 
E) zero V/m

Question 9

The plates of a parallel plate capacitor each have an area of 0.40 mS1U1P12S1S1P0 and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated.
-Suppose that a dielectric sheet is inserted to completely fill the space between the plates and the potential difference between the plates drops to 1000 V. Determine the dielectric constant.

Accepted Answer

A) 0.333 
B) 0.666 
C) 3.0 
D) 6.0 
E) 2000

Question 10

Complete the following statement: When a dielectric with constant $\kappa$ is inserted between the plates of a charged isolated capacitor

Accepted Answer

A) the capacitance is reduced by a factor $\kappa$. 
B) the charge on the plates is reduced by a factor of $\kappa$. 
C) the charge on the plates is increased by a factor of $\kappa$. 
D) the electric field between the plates is reduced by a factor of $\kappa$. 
E) the potential difference between the plates is increased by a factor of $\kappa$.

Question 11

A parallel plate capacitor has plates of area 2.0 × 10-3 m2 and plate separation 1.0 × 10-4 m. Air fills the volume between the plates. What potential difference is required to establish a 3.0 $\mu$C charge on the plates?

Accepted Answer

A) 9.3 × 102 V 
B) 2.4 × 104 V 
C) 1.7 × 104 V 
D) 6.9 × 103 V 
E) 3.7 × 105 V

Question 12

The sketch shows cross sections of equipotential surfaces between two charged conductors shown in solid black. Points on the equipotential surfaces near the conductors are labeled A, B, C, ..., H. 
-What is the direction of the electric field at point E?

Accepted Answer

A) toward G 
B) toward B 
C) toward H 
D) toward C 
E) toward F

Question 13

The plates of a parallel plate capacitor each have an area of 0.40 mS1U1P12S1S1P0 and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated.
-How much work is required to move a -4.0 $\mu$C charge from the negative plate to the positive plate of this system?

Accepted Answer

A) -1.2 × 10-2 J 
B) +1.2 × 10-2 J 
C) -2.4 × 10-2 J 
D) +2.4 × 10-2 J 
E) -5.4 × 10-2 J

Question 14

The effective area of each plate of a parallel plate capacitor is 2.1 m2. The capacitor is filled with neoprene rubber ($\kappa$ = 6.4). When a 6.0-V potential difference exists across the plates of the capacitor, the capacitor stores 4.0 µC of charge. Determine the plate separation of the capacitor.

Accepted Answer

A) 7.2 × 10-5 m 
B) 3.0 × 10-4 m 
C) 1.8 × 10-4 m 
D) 5.3 × 10-4 m 
E) 8.2 × 10-5 m

Question 15

Two charges of opposite sign and equal magnitude Q = 0.82 C are held 2.0 m apart as shown in the figure. 
-Determine the electric potential at the point P.

Accepted Answer

A) 1.1 × 109 V 
B) 2.2 × 109 V 
C) 4.5 × 109 V 
D) 9.0 × 109 V 
E) zero volts

Question 16

The plates of a parallel plate capacitor each have an area of 0.40 mS1U1P12S1S1P0 and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated.
-Determine the value of the capacitance.

Accepted Answer

A) 9.0 × 10-11 F 
B) 1.8 × 10-10 F 
C) 3.6 × 10-10 F 
D) 4.8 × 10-10 F 
E) 6.4 × 10-10 F

Question 17

A parallel plate capacitor has a potential difference between its plates of 1.6 V and a plate separation distance of 2.5 mm. What is the magnitude of the electric field if a material that has a dielectric constant of 3.4 is inserted between the plates?

Accepted Answer

A) 110 V/m 
B) 170 V/m 
C) 190 V/m 
D) 240 V/m 
E) 290 V/m

Question 18

Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. 
-What is the electric potential at P, the center of the square?

Accepted Answer

A) kQ/a 
B) 2kQ/a 
C) 4kQ/a 
D) kQ/4a 
E) zero volts

Question 19

Two positive charges are located at points A and B as shown in the figure. The distance from each charge to the point P is a = 2.0 m. 
-Determine the magnitude of the electric field at the point P.

Accepted Answer

A) 3.38 × 103 V/m 
B) 6.75 × 103 V/m 
C) 9.55 × 103 V/m 
D) 1.35 × 104 V/m 
E) 2.70 × 104 V/m

Question 20

The sketch shows cross sections of equipotential surfaces between two charged conductors shown in solid black. Points on the equipotential surfaces near the conductors are labeled A, B, C, ..., H. 
-What is the magnitude of the potential difference between points A and H?

Accepted Answer

A) 100 V 
B) 200 V 
C) 400 V 
D) 600 V 
E) 700 V

Exam 19: Electric Potential Energy and the Electric Potential

Which one of the following statements concerning electrostatic situations is false?

The magnitude of the charge on the plates of an isolated parallel plate capacitor is doubled. Which one of the following statements is true concerning the capacitance of this parallel-plate system?

Complete the following statement: The electron volt is a unit of

Which one of the following statements is true concerning the work done by an external force in moving an electron at constant speed between two points in an electrostatic field?

Three point charges -Q, -Q, and +3Q are arranged along a line as shown in the sketch. What is the electric potential at the point P?

P and Q are points within a uniform electric field that are separated by a distance of 0.2 m as shown. The potential difference between P and Q is 75 V. -Determine the magnitude of this electric field.

Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. -What is the magnitude of the electric field at P, the center of the square?

Complete the following statement: When a dielectric with constant $\kappa$ is inserted between the plates of a charged isolated capacitor

A parallel plate capacitor has plates of area 2.0 × 10^-³ m² and plate separation 1.0 × 10^-⁴ m. Air fills the volume between the plates. What potential difference is required to establish a 3.0 $\mu$ C charge on the plates?

The sketch shows cross sections of equipotential surfaces between two charged conductors shown in solid black. Points on the equipotential surfaces near the conductors are labeled A, B, C, ..., H. -What is the direction of the electric field at point E?

Two charges of opposite sign and equal magnitude Q = 0.82 C are held 2.0 m apart as shown in the figure. -Determine the electric potential at the point P.

The plates of a parallel plate capacitor each have an area of 0.40 m² and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated. -Determine the value of the capacitance.

A parallel plate capacitor has a potential difference between its plates of 1.6 V and a plate separation distance of 2.5 mm. What is the magnitude of the electric field if a material that has a dielectric constant of 3.4 is inserted between the plates?

Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. -What is the electric potential at P, the center of the square?

Two positive charges are located at points A and B as shown in the figure. The distance from each charge to the point P is a = 2.0 m. -Determine the magnitude of the electric field at the point P.

The sketch shows cross sections of equipotential surfaces between two charged conductors shown in solid black. Points on the equipotential surfaces near the conductors are labeled A, B, C, ..., H. -What is the magnitude of the potential difference between points A and H?

Exam 19: Electric Potential Energy and the Electric Potential

Which one of the following statements concerning electrostatic situations is false?

The magnitude of the charge on the plates of an isolated parallel plate capacitor is doubled. Which one of the following statements is true concerning the capacitance of this parallel-plate system?

Complete the following statement: The electron volt is a unit of

Which one of the following statements is true concerning the work done by an external force in moving an electron at constant speed between two points in an electrostatic field?

Three point charges -Q, -Q, and +3Q are arranged along a line as shown in the sketch. What is the electric potential at the point P?

P and Q are points within a uniform electric field that are separated by a distance of 0.2 m as shown. The potential difference between P and Q is 75 V. -Determine the magnitude of this electric field.

Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. -What is the magnitude of the electric field at P, the center of the square?

Complete the following statement: When a dielectric with constant κ\kappaκ is inserted between the plates of a charged isolated capacitor

A parallel plate capacitor has plates of area 2.0 × 10-3 m2 and plate separation 1.0 × 10-4 m. Air fills the volume between the plates. What potential difference is required to establish a 3.0 μ\muμ C charge on the plates?

The sketch shows cross sections of equipotential surfaces between two charged conductors shown in solid black. Points on the equipotential surfaces near the conductors are labeled A, B, C, ..., H. -What is the direction of the electric field at point E?

Two charges of opposite sign and equal magnitude Q = 0.82 C are held 2.0 m apart as shown in the figure. -Determine the electric potential at the point P.

The plates of a parallel plate capacitor each have an area of 0.40 m2 and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated. -Determine the value of the capacitance.

A parallel plate capacitor has a potential difference between its plates of 1.6 V and a plate separation distance of 2.5 mm. What is the magnitude of the electric field if a material that has a dielectric constant of 3.4 is inserted between the plates?

Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. -What is the electric potential at P, the center of the square?

Two positive charges are located at points A and B as shown in the figure. The distance from each charge to the point P is a = 2.0 m. -Determine the magnitude of the electric field at the point P.

The sketch shows cross sections of equipotential surfaces between two charged conductors shown in solid black. Points on the equipotential surfaces near the conductors are labeled A, B, C, ..., H. -What is the magnitude of the potential difference between points A and H?

Complete the following statement: When a dielectric with constant $\kappa$ is inserted between the plates of a charged isolated capacitor

A parallel plate capacitor has plates of area 2.0 × 10^-³ m² and plate separation 1.0 × 10^-⁴ m. Air fills the volume between the plates. What potential difference is required to establish a 3.0 $\mu$ C charge on the plates?

The plates of a parallel plate capacitor each have an area of 0.40 m² and are separated by a distance of 0.02 m. They are charged until the potential difference between the plates is 3000 V. The charged capacitor is then isolated. -Determine the value of the capacitance.