Question 1

When introduced into a region where an electric field is present, a proton with initial velocity   will eventually move

Accepted Answer

A)  along an electric field line, in the positive direction of the line. 
B)  along an electric field line, in the negative direction of the line. 
C)  to a point of decreased potential. 
D)  as described in both (a) and (c). 
A)  along an electric field line, in the positive direction of the line. 
B)  along an electric field line, in the negative direction of the line. 
C)  to a point of decreased potential. 
D)  as described in both (a) and (c).

Question 2

The gap between electrodes in a spark plug is 0.06 cm. In order to produce an electric spark in a gasoline-air mixture, the electric field must reach a value of 3 × 106 V/m. What minimum voltage must be supplied by the ignition circuit when starting the car?

Accepted Answer

Question 3

An uncharged metal sphere is placed on an insulating puck on a frictionless table. While being held parallel to the table, a rod with a charge q is brought close to the sphere, but does not touch it. As the rod is brought in, the sphere

Accepted Answer

A)  remains at rest. 
B)  moves toward the rod. 
C)  moves away from the rod. 
D)  moves perpendicular to the velocity vector of the rod. 
E)  moves upward off the puck. 
A)  remains at rest. 
B)  moves toward the rod. 
C)  moves away from the rod. 
D)  moves perpendicular to the velocity vector of the rod. 
E)  moves upward off the puck.

Question 4

A point charge of 6.0 nC is placed at the center of a hollow spherical conductor (inner radius = 1.0 cm, outer radius = 2.0 cm) which has a net charge of −4.0 nC. Determine the resulting charge density on the inner surface of the conducting sphere.

Accepted Answer

A)  +4.8 μC/m2 
B)  −4.8 μC/m2 
C)  −9.5 μC/m2 
D)  +9.5 μC/m2 
E)  −8.0 μC/m2 
A)  +4.8 μC/m2 
B)  −4.8 μC/m2 
C)  −9.5 μC/m2 
D)  +9.5 μC/m2 
E)  −8.0 μC/m2

Question 5

When a charged particle is moved along an electric field line,

Accepted Answer

A)  the electric field does no work on the charge. 
B)  the electrical potential energy of the charge does not change. 
C)  the electrical potential energy of the charge undergoes the maximum change in magnitude. 
D)  the voltage changes, but there is no change in electrical potential energy. 
E)  the electrical potential energy undergoes the maximum change, but there is no change in voltage. 
A)  the electric field does no work on the charge. 
B)  the electrical potential energy of the charge does not change. 
C)  the electrical potential energy of the charge undergoes the maximum change in magnitude. 
D)  the voltage changes, but there is no change in electrical potential energy. 
E)  the electrical potential energy undergoes the maximum change, but there is no change in voltage.

Question 6

The electric potential inside a charged solid spherical conductor in equilibrium

Accepted Answer

A)  is always zero. 
B)  is constant and equal to its value at the surface. 
C)  decreases from its value at the surface to a value of zero at the center. 
D)  increases from its value at the surface to a value at the center that is a multiple of the potential at the surface. 
E)  is equal to the charge passing through the surface per unit time divided by the resistance. 
A)  is always zero. 
B)  is constant and equal to its value at the surface. 
C)  decreases from its value at the surface to a value of zero at the center. 
D)  increases from its value at the surface to a value at the center that is a multiple of the potential at the surface. 
E)  is equal to the charge passing through the surface per unit time divided by the resistance.

Question 7

When a negative charge is released and moves along an electric field line, it moves to a position of

Accepted Answer

A)  lower potential and lower potential energy. 
B)  lower potential and higher potential energy. 
C)  higher potential and lower potential energy. 
D)  higher potential and higher potential energy. 
E)  decreasing magnitude of the electric field. 
A)  lower potential and lower potential energy. 
B)  lower potential and higher potential energy. 
C)  higher potential and lower potential energy. 
D)  higher potential and higher potential energy. 
E)  decreasing magnitude of the electric field.

Question 8

Identical point charges (+20 μC) are placed at the corners of an equilateral triangle with sides of 2.0-m length. How much external energy is required to bring a charge of 45 μC from infinity to the midpoint of one side of the triangle?

Accepted Answer

A)  26 J 
B)  16 J 
C)  23 J 
D)  21 J 
E)  12 J 
A)  26 J 
B)  16 J 
C)  23 J 
D)  21 J 
E)  12 J

Question 9

A proton (mass = 1.67 × 10−27 kg, charge = 1.60 × 10−19 C) moves from point A to point B under the influence of an electrostatic force only. At point A the proton moves with a speed of 60 km/s. At point B the speed of the proton is 80 km/s. Determine the potential difference VB − VA.

Accepted Answer

A)  +15 V 
B)  −15 V 
C)  −33 V 
D)  +33 V 
E)  −20 V 
A)  +15 V 
B)  −15 V 
C)  −33 V 
D)  +33 V 
E)  −20 V

Question 10

Two charges lie on the x axis, +2q at the origin, and −3q at x = 5.0 m. The point on the x axis where the electric potential has a zero value (when the value at infinity is also zero) is

Accepted Answer

A)  1.0 m. 
B)  2.0 m. 
C)  2.5 m. 
D)  3.0 m. 
E)  4.0 m. 
A)  1.0 m. 
B)  2.0 m. 
C)  2.5 m. 
D)  3.0 m. 
E)  4.0 m.

Question 11

When introduced into a region where an electric field is present, an electron with initial velocity   will eventually move

Accepted Answer

A)  along an electric field line, in the positive direction of the line. 
B)  along an electric field line, in the negative direction of the line. 
C)  to a point of decreased potential. 
D)  to a point of increased potential. 
E)  as described in both (b) and (d). 
A)  along an electric field line, in the positive direction of the line. 
B)  along an electric field line, in the negative direction of the line. 
C)  to a point of decreased potential. 
D)  to a point of increased potential. 
E)  as described in both (b) and (d).

Question 12

A system consisting of a positively-charged particle and an electric field

Accepted Answer

A)  loses potential difference and kinetic energy when the charged particle moves in the direction of the field. 
B)  loses electric potential energy when the charged particle moves in the direction of the field. 
C)  loses kinetic energy when the charged particle moves in the direction of the field. 
D)  gains electric potential energy when the charged particle moves in the direction of the field. 
E)  gains potential difference and electric potential energy when the charged particle moves in the direction of the field. 
A)  loses potential difference and kinetic energy when the charged particle moves in the direction of the field. 
B)  loses electric potential energy when the charged particle moves in the direction of the field. 
C)  loses kinetic energy when the charged particle moves in the direction of the field. 
D)  gains electric potential energy when the charged particle moves in the direction of the field. 
E)  gains potential difference and electric potential energy when the charged particle moves in the direction of the field.

Question 13

Identical 4.0-μC charges are placed on the y axis at y = ±4.0 m. Point A is on the x axis at x = +3.0 m. Determine the electric potential of point A (relative to zero at the origin).

Accepted Answer

A)  −4.5 kV 
B)  −2.7 kV 
C)  −1.8 kV 
D)  −3.6 kV 
E)  −14 kV 
A)  −4.5 kV 
B)  −2.7 kV 
C)  −1.8 kV 
D)  −3.6 kV 
E)  −14 kV

Question 14

A charge of 20 nC is distributed uniformly along the x axis from x = −2.0 m to x = +2.0 m. What is the electric potential (relative to zero at infinity) at the point x = 5.0 m on the x axis?

Accepted Answer

A)  57 V 
B)  48 V 
C)  38 V 
D)  67 V 
E)  100 V 
A)  57 V 
B)  48 V 
C)  38 V 
D)  67 V 
E)  100 V

Question 15

Two charges lie on the x axis, +3q at the origin, and −2q at x = 5.0 m. The point on the x axis where the electric potential has a zero value (when the value at infinity is also zero) is

Accepted Answer

A)  1.0 m. 
B)  2.0 m. 
C)  2.5 m. 
D)  3.0 m. 
E)  4.0 m. 
A)  1.0 m. 
B)  2.0 m. 
C)  2.5 m. 
D)  3.0 m. 
E)  4.0 m.

Question 16

A particle (mass = 6.7 × 10−27 kg, charge = 3.2 × 10−19 C) moves along the positive x axis with a speed of 4.8 × 105 m/s. It enters a region of uniform electric field parallel to its motion and comes to rest after moving 2.0 m into the field. What is the magnitude of the electric field?

Accepted Answer

A)  2.0 kN/C 
B)  1.5 kN/C 
C)  1.2 kN/C 
D)  3.5 kN/C 
E)  2.4 kN/C 
A)  2.0 kN/C 
B)  1.5 kN/C 
C)  1.2 kN/C 
D)  3.5 kN/C 
E)  2.4 kN/C

Question 17

Four electrons move from point A to point B in a uniform electric field as shown below. Rank the electrons in diagrams I through IV by the changes in potential energy from most positive to most negative when traveling from A to B.

Accepted Answer

A)  I = II = III = IV. 
B)  II = III > I > IV. 
C)  III > I = IV > II. 
D)  II > I = IV > III. 
E)  I > II = III > IV. 
A)  I = II = III = IV. 
B)  II = III > I > IV. 
C)  III > I = IV > II. 
D)  II > I = IV > III. 
E)  I > II = III > IV.

Question 18

The Bohr model pictures a hydrogen atom in its ground state as a proton and an electron separated by the distance a0 = 0.529 × 10−10 m. The electric potential created by the electron at the position of the proton is

Accepted Answer

A)  −13.6 V. 
B)  +13.6 V. 
C)  −27.2 V. 
D)  +27.2 V. 
E)  +5.12 × 109 V. 
A)  −13.6 V. 
B)  +13.6 V. 
C)  −27.2 V. 
D)  +27.2 V. 
E)  +5.12 × 109 V.

Question 19

A nonconducting sphere of radius 10 cm is charged uniformly with a density of 100 nC/m3. What is the magnitude of the potential difference between the center and a point 4.0 cm away?

Accepted Answer

A)  12 V 
B)  6.8 V 
C)  3.0 V 
D)  4.7 V 
E)  2.2 V 
A)  12 V 
B)  6.8 V 
C)  3.0 V 
D)  4.7 V 
E)  2.2 V

Question 20

A particle (charge 7.5 μC) is released from rest at a point on the x axis, x = 10 cm. It begins to move due to the presence of a 2.0-μC charge which remains fixed at the origin. What is the kinetic energy of the particle at the instant it passes the point x = 1.0 m?

Accepted Answer

A)  3.0 J 
B)  1.8 J 
C)  2.4 J 
D)  1.2 J 
E)  1.4 J 
A)  3.0 J 
B)  1.8 J 
C)  2.4 J 
D)  1.2 J 
E)  1.4 J

Exam 25: Electric Potential

When introduced into a region where an electric field is present, a proton with initial velocity will eventually move

The gap between electrodes in a spark plug is 0.06 cm. In order to produce an electric spark in a gasoline-air mixture, the electric field must reach a value of 3 × 106 V/m. What minimum voltage must be supplied by the ignition circuit when starting the car?

An uncharged metal sphere is placed on an insulating puck on a frictionless table. While being held parallel to the table, a rod with a charge q is brought close to the sphere, but does not touch it. As the rod is brought in, the sphere

A point charge of 6.0 nC is placed at the center of a hollow spherical conductor (inner radius = 1.0 cm, outer radius = 2.0 cm) which has a net charge of −4.0 nC. Determine the resulting charge density on the inner surface of the conducting sphere.

When a charged particle is moved along an electric field line,

The electric potential inside a charged solid spherical conductor in equilibrium

When a negative charge is released and moves along an electric field line, it moves to a position of

Identical point charges (+20 μC) are placed at the corners of an equilateral triangle with sides of 2.0-m length. How much external energy is required to bring a charge of 45 μC from infinity to the midpoint of one side of the triangle?

A proton (mass = 1.67 × 10−27 kg, charge = 1.60 × 10−19 C) moves from point A to point B under the influence of an electrostatic force only. At point A the proton moves with a speed of 60 km/s. At point B the speed of the proton is 80 km/s. Determine the potential difference VB − VA.

Two charges lie on the x axis, +2q at the origin, and −3q at x = 5.0 m. The point on the x axis where the electric potential has a zero value (when the value at infinity is also zero) is

When introduced into a region where an electric field is present, an electron with initial velocity will eventually move

A system consisting of a positively-charged particle and an electric field

Identical 4.0-μC charges are placed on the y axis at y = ±4.0 m. Point A is on the x axis at x = +3.0 m. Determine the electric potential of point A (relative to zero at the origin).

A charge of 20 nC is distributed uniformly along the x axis from x = −2.0 m to x = +2.0 m. What is the electric potential (relative to zero at infinity) at the point x = 5.0 m on the x axis?

Two charges lie on the x axis, +3q at the origin, and −2q at x = 5.0 m. The point on the x axis where the electric potential has a zero value (when the value at infinity is also zero) is

A particle (mass = 6.7 × 10−27 kg, charge = 3.2 × 10−19 C) moves along the positive x axis with a speed of 4.8 × 105 m/s. It enters a region of uniform electric field parallel to its motion and comes to rest after moving 2.0 m into the field. What is the magnitude of the electric field?

Four electrons move from point A to point B in a uniform electric field as shown below. Rank the electrons in diagrams I through IV by the changes in potential energy from most positive to most negative when traveling from A to B.

The Bohr model pictures a hydrogen atom in its ground state as a proton and an electron separated by the distance a0 = 0.529 × 10−10 m. The electric potential created by the electron at the position of the proton is

A nonconducting sphere of radius 10 cm is charged uniformly with a density of 100 nC/m3. What is the magnitude of the potential difference between the center and a point 4.0 cm away?

A particle (charge 7.5 μC) is released from rest at a point on the x axis, x = 10 cm. It begins to move due to the presence of a 2.0-μC charge which remains fixed at the origin. What is the kinetic energy of the particle at the instant it passes the point x = 1.0 m?

Physics and Measurement

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The Laws of Motion

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Image Formation

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Introduction to Quantum Physics

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The gap between electrodes in a spark plug is 0.06 cm. In order to produce an electric spark in a gasoline-air mixture, the electric field must reach a value of 3 × 10⁶ V/m. What minimum voltage must be supplied by the ignition circuit when starting the car?

The Bohr model pictures a hydrogen atom in its ground state as a proton and an electron separated by the distance a₀ = 0.529 × 10−¹⁰ m. The electric potential created by the electron at the position of the proton is

A nonconducting sphere of radius 10 cm is charged uniformly with a density of 100 nC/m³. What is the magnitude of the potential difference between the center and a point 4.0 cm away?