Question 1

At the instant the negatively charged body is at the origin, the magnetic field at point P due to its motion is in the negative x direction. The charged body must be moving

Accepted Answer

A)  in the negative z direction. 
B)  in the positive y direction. 
C)  in the positive x direction. 
D)  in the negative y direction. 
E)  in the positive z direction.

Question 2

Four wires carry equal currents along the four parallel edges of a cube. A parallel current-carrying wire through the center of the cube is free to move. The vector that might represent the direction in which the center wire will move is

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 3

Two current-carrying wires are perpendicular to each other. The current in one flows vertically upward and the current in the other flows horizontally toward the east. The horizontal wire is 1 m south of the vertical wire. What is the direction of the net magnetic force on the horizontal wire?

Accepted Answer

A)  north 
B)  east 
C)  west 
D)  south 
E)  There is no net magnetic force on the horizontal wire.

Question 4

Cobalt has a density of 8.90 g/cm3 and a molecular mass of 58.9 g/mol. Its magnetic moment is 1.69 Bohr magnetons (1 Bohr magneton = 9.27 *10-24 A · m2). What is its saturation magnetization?

Accepted Answer

A)  1.43* 109 A/m 
B)  9.10* 105 A/m 
C)  1.43 * 106 A/m 
D)  9.10 *1028 A/m 
E)  1.69 * 105 A/m

Question 5

A point charge is moving with speed 2 *107 m/s along the x axis. At t = 0, the charge is at x = 0 m and the magnitude of the magnetic field at x = 4 m is B0. The magnitude of the magnetic field at x = 4m when t = 0.1 $\mu$s is

Accepted Answer

A)  B0/2 
B)  B0 
C)  B0/4 
D)  2B0 
E)  4B0

Question 6

If the Biot-Savart relationship d  = ($\mu$0/4 $\pi$)(  *  d  )/r3
Is used to determine the magnetic field at the point P on the axis of a circular current-carrying loop, the vector  is correctly represented by

Accepted Answer

A)   1  
B)   2  
C)   3  
D)   4  
E)   5

Question 7

If the magnetic susceptibility of a material is positive,

Accepted Answer

A)  paramagnetic effects must be greater than diamagnetic effects. 
B)  diamagnetic effects must be greater than paramagnetic effects. 
C)  diamagnetic effects must be greater than ferromagnetic effects. 
D)  ferromagnetic effects must be greater than paramagnetic effects. 
E)  paramagnetic effects must be greater than ferromagnetic effects.

Question 8

Ampère's law is valid

Accepted Answer

A)  when there is a high degree of symmetry in the geometry of the situation. 
B)  when there is no symmetry. 
C)  when the current is constant. 
D)  when the magnetic field is constant. 
E)  for all of these conditions.

Question 9

A wire of radius 0.6 cm carries a current of 10 A that is uniformly distributed over its cross section. Calculate the magnetic field strength at r = 0.2 cm divided by that at r = 0.4 cm.

Accepted Answer

A)  1.0 
B)  0.75 
C)  0.50 
D)  2.0 
E)  3.0

Question 10

A positively charged body is moving in the negative z direction as shown. The direction of the magnetic field due to the motion of this charged body at point P is

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 11

Current-carrying wires are located along two edges of a cube with the directions of the currents as indicated. The vector that indicates the resultant magnetic field at the corner of the cube is

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 12

A long conductor carrying current I lies in the xz plane parallel to the z axis. The current travels in the negative z direction, as shown in the figure. The vector that represents the magnetic field at the origin O is

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 13

Two long, parallel wires are spaced 1 m apart in air, and you have established a current of 1 A in each. The force per unit length that each wire exerts on the other is

Accepted Answer

A)  4$\mu$$\pi$0  
B)  2 $\mu$$\pi$0  
C)   $\mu$0  
D)   $\mu$0/4 $\pi$ 
E)  $\mu$0/2 $\pi$

Question 14

A particle with charge q = 5 $\mu$C is moving with velocity  . At t = 0, it is located at the origin. The magnetic field at  at t = 0 is

Accepted Answer

A)   
B)   
C)   
D)   
E)  None of these is correct.

Question 15

A circular loop of wire of radius 6.0 cm has 30 turns and lies in the xy plane. It carries a current of 5 A in such a direction that the magnetic moment of the loop is along the x axis. The magnetic field on the x axis at x = 6.0 cm is approximately

Accepted Answer

A)  19$\mu$T 
B)  0.56 mT 
C)  0.11 mT 
D)  47 $\mu$T 
E)  0.88 mT

Question 16

A circular loop of wire 1.0 cm in radius carries a current of 30 A. The magnetic field at the center of the loop is

Accepted Answer

A)  1.9 mT 
B)  2.4 mT 
C)  3.8 mT 
D)  12$\mu$T 
E)  48 $\mu$T

Question 17

Use the following figure to answer the next problem: 
-The tightly wound toroid shown consists of 100 turns of wire, each carrying a current
I = 3 A. If a = 12 cm and b = 15 cm, the magnetic field at r = 13 cm, due to the current in this toroid, is (µ0 = 4 $\pi$ *10-7 N/A2)

Accepted Answer

A)  333 µT 
B)  462 µT 
C)  500 µT 
D)  600 
E)  zero

Question 18

Two positively charged bodies are moving in opposite directions on parallel paths that lie in the xz plane. Their speeds are equal and their trajectories are equidistant from the x axis. The magnetic field at the origin, due to the motion of these charged bodies will be

Accepted Answer

A)  in the x direction. 
B)  in the y direction. 
C)  in all directions. 
D)  in the z direction. 
E)  zero.

Question 19

A positively charged body is moving in the positive x direction as shown. The direction of the magnetic field at the origin due to the motion of this charged body is

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  None of these is correct, as this charged body does not create a magnetic field along the axis of its motion.

Question 20

Calculate the magnetic field and its direction at point P, which is 2.0 cm away from the top wire and 4.0 cm from the bottom wire. Assume both wires are infinitely long and each carries a current of 1.5 A.

Accepted Answer

A)  2.3 *10-5 T directed OUT of the page 
B)  7.5 *10-6 T directed INTO the page 
C)  2.3 *10-5 T directed INTO the page 
D)  7.5 * 10-6 T directed OUT of the page 
E)  1.1 * 10-5 T directed OUT of the page

Exam 7: Sources of the Magnetic Field

At the instant the negatively charged body is at the origin, the magnetic field at point P due to its motion is in the negative x direction. The charged body must be moving

Four wires carry equal currents along the four parallel edges of a cube. A parallel current-carrying wire through the center of the cube is free to move. The vector that might represent the direction in which the center wire will move is

Two current-carrying wires are perpendicular to each other. The current in one flows vertically upward and the current in the other flows horizontally toward the east. The horizontal wire is 1 m south of the vertical wire. What is the direction of the net magnetic force on the horizontal wire?

Cobalt has a density of 8.90 g/cm³ and a molecular mass of 58.9 g/mol. Its magnetic moment is 1.69 Bohr magnetons (1 Bohr magneton = 9.27 *10^-24 A · m²) . What is its saturation magnetization?

A point charge is moving with speed 2 *10⁷ m/s along the x axis. At t = 0, the charge is at x = 0 m and the magnitude of the magnetic field at x = 4 m is B₀. The magnitude of the magnetic field at x = 4m when t = 0.1 $\mu$ s is

If the magnetic susceptibility of a material is positive,

Ampère's law is valid

A wire of radius 0.6 cm carries a current of 10 A that is uniformly distributed over its cross section. Calculate the magnetic field strength at r = 0.2 cm divided by that at r = 0.4 cm.

A positively charged body is moving in the negative z direction as shown. The direction of the magnetic field due to the motion of this charged body at point P is

Current-carrying wires are located along two edges of a cube with the directions of the currents as indicated. The vector that indicates the resultant magnetic field at the corner of the cube is

A long conductor carrying current I lies in the xz plane parallel to the z axis. The current travels in the negative z direction, as shown in the figure. The vector that represents the magnetic field at the origin O is

Two long, parallel wires are spaced 1 m apart in air, and you have established a current of 1 A in each. The force per unit length that each wire exerts on the other is

A circular loop of wire of radius 6.0 cm has 30 turns and lies in the xy plane. It carries a current of 5 A in such a direction that the magnetic moment of the loop is along the x axis. The magnetic field on the x axis at x = 6.0 cm is approximately

A circular loop of wire 1.0 cm in radius carries a current of 30 A. The magnetic field at the center of the loop is

Two positively charged bodies are moving in opposite directions on parallel paths that lie in the xz plane. Their speeds are equal and their trajectories are equidistant from the x axis. The magnetic field at the origin, due to the motion of these charged bodies will be

A positively charged body is moving in the positive x direction as shown. The direction of the magnetic field at the origin due to the motion of this charged body is

Calculate the magnetic field and its direction at point P, which is 2.0 cm away from the top wire and 4.0 cm from the bottom wire. Assume both wires are infinitely long and each carries a current of 1.5 A.

Exam 7: Sources of the Magnetic Field

At the instant the negatively charged body is at the origin, the magnetic field at point P due to its motion is in the negative x direction. The charged body must be moving

Four wires carry equal currents along the four parallel edges of a cube. A parallel current-carrying wire through the center of the cube is free to move. The vector that might represent the direction in which the center wire will move is

Two current-carrying wires are perpendicular to each other. The current in one flows vertically upward and the current in the other flows horizontally toward the east. The horizontal wire is 1 m south of the vertical wire. What is the direction of the net magnetic force on the horizontal wire?

Cobalt has a density of 8.90 g/cm3 and a molecular mass of 58.9 g/mol. Its magnetic moment is 1.69 Bohr magnetons (1 Bohr magneton = 9.27 *10-24 A · m2) . What is its saturation magnetization?

A point charge is moving with speed 2 *107 m/s along the x axis. At t = 0, the charge is at x = 0 m and the magnitude of the magnetic field at x = 4 m is B0. The magnitude of the magnetic field at x = 4m when t = 0.1 μ\muμ s is

If the Biot-Savart relationship d = ( μ\muμ 0/4 π\piπ ) ( * d ) /r3 Is used to determine the magnetic field at the point P on the axis of a circular current-carrying loop, the vector is correctly represented by

If the magnetic susceptibility of a material is positive,

Ampère's law is valid

A wire of radius 0.6 cm carries a current of 10 A that is uniformly distributed over its cross section. Calculate the magnetic field strength at r = 0.2 cm divided by that at r = 0.4 cm.

A positively charged body is moving in the negative z direction as shown. The direction of the magnetic field due to the motion of this charged body at point P is

Current-carrying wires are located along two edges of a cube with the directions of the currents as indicated. The vector that indicates the resultant magnetic field at the corner of the cube is

A long conductor carrying current I lies in the xz plane parallel to the z axis. The current travels in the negative z direction, as shown in the figure. The vector that represents the magnetic field at the origin O is

Two long, parallel wires are spaced 1 m apart in air, and you have established a current of 1 A in each. The force per unit length that each wire exerts on the other is

A particle with charge q = 5 μ\muμ C is moving with velocity . At t = 0, it is located at the origin. The magnetic field at at t = 0 is

A circular loop of wire of radius 6.0 cm has 30 turns and lies in the xy plane. It carries a current of 5 A in such a direction that the magnetic moment of the loop is along the x axis. The magnetic field on the x axis at x = 6.0 cm is approximately

A circular loop of wire 1.0 cm in radius carries a current of 30 A. The magnetic field at the center of the loop is

Use the following figure to answer the next problem: -The tightly wound toroid shown consists of 100 turns of wire, each carrying a current I = 3 A. If a = 12 cm and b = 15 cm, the magnetic field at r = 13 cm, due to the current in this toroid, is (µ0 = 4 π\piπ *10-7 N/A2)

Two positively charged bodies are moving in opposite directions on parallel paths that lie in the xz plane. Their speeds are equal and their trajectories are equidistant from the x axis. The magnetic field at the origin, due to the motion of these charged bodies will be

A positively charged body is moving in the positive x direction as shown. The direction of the magnetic field at the origin due to the motion of this charged body is

Calculate the magnetic field and its direction at point P, which is 2.0 cm away from the top wire and 4.0 cm from the bottom wire. Assume both wires are infinitely long and each carries a current of 1.5 A.

Cobalt has a density of 8.90 g/cm³ and a molecular mass of 58.9 g/mol. Its magnetic moment is 1.69 Bohr magnetons (1 Bohr magneton = 9.27 *10^-24 A · m²) . What is its saturation magnetization?

A point charge is moving with speed 2 *10⁷ m/s along the x axis. At t = 0, the charge is at x = 0 m and the magnitude of the magnetic field at x = 4 m is B₀. The magnitude of the magnetic field at x = 4m when t = 0.1 $\mu$ s is