Question 1

On the average, in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.

Accepted Answer

A)   antiparallel
B)   parallel
C)   perpendicular
D)   alternately parallel and antiparallel
E)   randomly relativeF) A) and D)
G) B) and E)

Question 2

A long wire carries a current of 3.0 A along the axis of a long solenoid (radius = 3.0 cm, n = 900 turns/m, current = 30 mA) . What is the magnitude of the magnetic field at a point 2.0 cm from the axis of the solenoid? Neglect any end effects.

Accepted Answer

A)   34 μT
B)   64 μT
C)   30 μT
D)   45 μT
E)   4.0 μTF) A) and D)
G) B) and C)

Question 3

Two wires, each having a weight per unit length of 1.0 × 10−4 N/m, are strung parallel, one 0.10 m above the other. If the wires carry the same current, though in opposite directions, how great must the current in each wire be for the magnetic field of the lower conductor to balance the weight of the upper conductor?

Accepted Answer

Question 4

The figure shows a cross section of three parallel wires each carrying a current of 15 A. The currents in wires A and C are out of the paper, while that in wire B is into the paper. If the distance R = 5.0 mm, what is the magnitude of the force on a 4.0-m length of wire C?

Accepted Answer

A)   90 mN
B)   54 mN
C)   30 mN
D)   18 mN
E)   36 mNF) A) and E)
G) B) and C)

Question 5

The magnetic moment of an electron (charge = −e; mass = me)  moving in a circular orbit of radius r with speed v about a nucleus of mass mN is proportional to

Accepted Answer

A)   r.
B)   v.
C)   vr.
D)   evr.
E)   mNvr.F) B) and C)
G) B) and D)

Question 6

The planetary model of the hydrogen atom consists of an electron in a circular orbit about a proton. The motion of the electron of charge 1.60 × 10−19 C creates an electric current. The radius of the electron orbit is 5.30 × 10−11 m and the electron's velocity is 2.20 × 106 m/s. What is the magnetic field strength at the location of the proton?

Accepted Answer

Question 7

A long, straight wire (radius = 2.0 mm)  carries a current of 2.0 A distributed uniformly over a cross section perpendicular to the axis of the wire. What is the magnitude of the magnetic field at a distance of 1.0 mm from the axis of the wire?

Accepted Answer

A)   0.40 mT
B)   0.80 mT
C)   0.10 mT
D)   0.20 mT
E)   0.75 mTF) A) and B)
G) A) and C)

Question 8

Two solenoids of equal length are each made of 2000 turns of copper wire per meter. Solenoid I has a 5.00 cm radius; solenoid II a 10.0 cm radius. When equal currents are present in the two solenoids, the ratio of the magnitude of the magnetic field BI along the axis of solenoid I to the magnitude of the magnetic field BII along the axis of solenoid II, BI/BII, is

Accepted Answer

A)   1/4.
B)   1/2.
C)   1.
D)   2.
E)   4.F) A) and B)
G) None of the above

Question 9

A hollow cylindrical (inner radius = 1.0 mm, outer radius = 3.0 mm)  conductor carries a current of 80 A parallel to its axis. This current is uniformly distributed over a cross section of the conductor. Determine the magnitude of the magnetic field at a point that is 2.0 mm from the axis of the conductor.

Accepted Answer

A)   8.0 mT
B)   3.0 mT
C)   5.3 mT
D)   16 mT
E)   1.2 mTF) A) and E)
G) A) and D)

Question 10

A long cylindrical wire (radius = 2.0 cm)  carries a current of 40 A that is uniformly distributed over a cross section of the wire. What is the magnitude of the magnetic field at a point which is 1.5 cm from the axis of the wire?

Accepted Answer

A)   0.53 mT
B)   28 mT
C)   0.30 mT
D)   40 mT
E)   1.9 mTF) A) and E)
G) A) and D)

Question 11

What is the magnitude of the magnetic field at point P if a = R and b = 2R?

Accepted Answer

A)  
B)  
C)  
D)  
E)  F) C) and E)
G) All of the above

Question 12

By using a compass to measure the magnetic field direction at various points adjacent to a long straight wire, you can show that the wire's magnetic field lines are

Accepted Answer

A)   straight lines in space that go from one magnetic charge to another.
B)   straight lines in space that are parallel to the wire.
C)   straight lines in space that are perpendicular to the wire.
D)   circles that have their centers on the wire and lie in planes perpendicular to the wire.
E)   circles that have the wire lying along a diameter of the circle.F) A) and B)
G) C) and D)

Question 13

A straight wire (length = 8.0 m)  is bent to form a square. If the wire carries a current of 20 A, what is the magnitude of the magnetic field at the center of the square?

Accepted Answer

A)   17 μT
B)   14 μT
C)   11 μT
D)   20 μT
E)   36 μTF) C) and D)
G) A) and B)

Question 14

Two long parallel wires separated by 5.0 mm each carry a current of 60 A. These two currents are oppositely directed. What is the magnitude of the magnetic field at a point that is between the two wires and 2.0 mm from one of the two wires?

Accepted Answer

A)   2.0 mT
B)   10 mT
C)   8.0 mT
D)   1.6 mT
E)   7.2 mTF) B) and E)
G) C) and E)

Question 15

A segment of wire of total length 2.0 m is formed into a circular loop having 5.0 turns. If the wire carries a 1.2-A current, determine the magnitude of the magnetic field at the center of the loop.

Accepted Answer

A)   79 μT
B)   69 μT
C)   59 μT
D)   89 μT
E)   9.4 μTF) D) and E)
G) A) and E)

Question 16

A long wire is known to have a radius greater than 4.0 mm and to carry a current uniformly distributed over its cross section. If the magnitude of the magnetic field is 0.285 mT at a point 4.0 mm from the axis of the wire and 0.200 mT at a point 10 mm from the axis, what is the radius of the wire?

Accepted Answer

A)   4.6 mm
B)   7.1 mm
C)   5.3 mm
D)   12 mm
E)   10 mmF) A) and E)
G) A) and D)

Question 17

A current-carrying 2.0-cm long segment of wire is inside a long solenoid (radius = 4.0 cm, n = 800 turns/m, current = 50 mA) . The wire segment is oriented perpendicularly to the axis of the solenoid. If the current in the wire segment is 12 A, what is the magnitude of the magnetic force on this segment?

Accepted Answer

A)   22 μN
B)   16 μN
C)   18 μN
D)   12 μN
E)   0 μNF) All of the above
G) A) and C)

Question 18

Two long parallel wires are separated by 2.0 cm. The current in one of the wires is three times the other current. If the magnitude of the force on a 2.0-m length of one of the wires is equal to 60 μN, what is the greater of the two currents?

Accepted Answer

A)   2.0 A
B)   1.0 A
C)   3.0 A
D)   9.0 A
E)   1.5 AF) None of the above
G) A) and B)

Question 19

Two parallel and coaxial current loops of radius a are placed a distance 2L apart. When you look along the axis at the loops, the current in one is clockwise, and counterclockwise in the other. At a point on the axis half way between the loops the magnetic field in T has magnitude

Accepted Answer

A)   0.
B)   .
C)   .
D)   .
E)   .F) A) and D)
G) B) and C)

Question 20

Three coplanar parallel straight wires carry equal currents I to the right as shown below. Each pair of wires is a distance a apart. The direction of the magnetic force on the middle wire

Accepted Answer

A)   is up out of the plane of the wires.
B)   is down into the plane of the wires.
C)   is in the plane of the wires, directed upwards.
D)   is in the plane of the wires, directed downwards
E)   cannot be defined, because there is no magnetic force on the middle wire.F) A) and D)
G) B) and E)

Exam 30: Sources of the Magnetic Field

Three coplanar parallel straight wires carry equal currents I to the right as shown below. Each pair of wires is a distance a apart. The direction of the magnetic force on the middle wire

Correct Answer
verified

On the average, in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.

Correct Answer
verified

Correct Answer
verified

Two long parallel wires separated by 5.0 mm each carry a current of 60 A. These two currents are oppositely directed. What is the magnitude of the magnetic field at a point that is between the two wires and 2.0 mm from one of the two wires?

Correct Answer
verified

By using a compass to measure the magnetic field direction at various points adjacent to a long straight wire, you can show that the wire's magnetic field lines are

Correct Answer
verified

The figure shows a cross section of three parallel wires each carrying a current of 15 A. The currents in wires A and C are out of the paper, while that in wire B is into the paper. If the distance R = 5.0 mm, what is the magnitude of the force on a 4.0-m length of wire C?

Correct Answer
verified

Correct Answer
verified

A straight wire (length = 8.0 m) is bent to form a square. If the wire carries a current of 20 A, what is the magnitude of the magnetic field at the center of the square?

Correct Answer
verified

A long wire carries a current of 3.0 A along the axis of a long solenoid (radius = 3.0 cm, n = 900 turns/m, current = 30 mA) . What is the magnitude of the magnetic field at a point 2.0 cm from the axis of the solenoid? Neglect any end effects.

Correct Answer
verified

Correct Answer
verified

Two long parallel wires are separated by 2.0 cm. The current in one of the wires is three times the other current. If the magnitude of the force on a 2.0-m length of one of the wires is equal to 60 μN, what is the greater of the two currents?

Correct Answer
verified

Correct Answer
verified

A long cylindrical wire (radius = 2.0 cm) carries a current of 40 A that is uniformly distributed over a cross section of the wire. What is the magnitude of the magnetic field at a point which is 1.5 cm from the axis of the wire?

Correct Answer
verified

The magnetic moment of an electron (charge = −e; mass = m_e) moving in a circular orbit of radius r with speed v about a nucleus of mass m_N is proportional to

Correct Answer
verified

Two parallel and coaxial current loops of radius a are placed a distance 2L apart. When you look along the axis at the loops, the current in one is clockwise, and counterclockwise in the other. At a point on the axis half way between the loops the magnetic field in T has magnitude

Correct Answer
verified

A long, straight wire (radius = 2.0 mm) carries a current of 2.0 A distributed uniformly over a cross section perpendicular to the axis of the wire. What is the magnitude of the magnetic field at a distance of 1.0 mm from the axis of the wire?

Correct Answer
verified

What is the magnitude of the magnetic field at point P if a = R and b = 2R?

Correct Answer
verified

A segment of wire of total length 2.0 m is formed into a circular loop having 5.0 turns. If the wire carries a 1.2-A current, determine the magnitude of the magnetic field at the center of the loop.

Correct Answer
verified

A long wire is known to have a radius greater than 4.0 mm and to carry a current uniformly distributed over its cross section. If the magnitude of the magnetic field is 0.285 mT at a point 4.0 mm from the axis of the wire and 0.200 mT at a point 10 mm from the axis, what is the radius of the wire?

Correct Answer
verified

Correct Answer
verified

Exam 30: Sources of the Magnetic Field

Three coplanar parallel straight wires carry equal currents I to the right as shown below. Each pair of wires is a distance a apart. The direction of the magnetic force on the middle wire

Correct AnswerverifiedShow Answer

On the average, in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Two long parallel wires separated by 5.0 mm each carry a current of 60 A. These two currents are oppositely directed. What is the magnitude of the magnetic field at a point that is between the two wires and 2.0 mm from one of the two wires?

Correct AnswerverifiedShow Answer

By using a compass to measure the magnetic field direction at various points adjacent to a long straight wire, you can show that the wire's magnetic field lines are

Correct AnswerverifiedShow Answer

The figure shows a cross section of three parallel wires each carrying a current of 15 A. The currents in wires A and C are out of the paper, while that in wire B is into the paper. If the distance R = 5.0 mm, what is the magnitude of the force on a 4.0-m length of wire C?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A straight wire (length = 8.0 m) is bent to form a square. If the wire carries a current of 20 A, what is the magnitude of the magnetic field at the center of the square?

Correct AnswerverifiedShow Answer

A long wire carries a current of 3.0 A along the axis of a long solenoid (radius = 3.0 cm, n = 900 turns/m, current = 30 mA) . What is the magnitude of the magnetic field at a point 2.0 cm from the axis of the solenoid? Neglect any end effects.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Two long parallel wires are separated by 2.0 cm. The current in one of the wires is three times the other current. If the magnitude of the force on a 2.0-m length of one of the wires is equal to 60 μN, what is the greater of the two currents?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A long cylindrical wire (radius = 2.0 cm) carries a current of 40 A that is uniformly distributed over a cross section of the wire. What is the magnitude of the magnetic field at a point which is 1.5 cm from the axis of the wire?

Correct AnswerverifiedShow Answer

The magnetic moment of an electron (charge = −e; mass = me) moving in a circular orbit of radius r with speed v about a nucleus of mass mN is proportional to

Correct AnswerverifiedShow Answer

Two parallel and coaxial current loops of radius a are placed a distance 2L apart. When you look along the axis at the loops, the current in one is clockwise, and counterclockwise in the other. At a point on the axis half way between the loops the magnetic field in T has magnitude

Correct AnswerverifiedShow Answer

A long, straight wire (radius = 2.0 mm) carries a current of 2.0 A distributed uniformly over a cross section perpendicular to the axis of the wire. What is the magnitude of the magnetic field at a distance of 1.0 mm from the axis of the wire?

Correct AnswerverifiedShow Answer

What is the magnitude of the magnetic field at point P if a = R and b = 2R?

Correct AnswerverifiedShow Answer

A segment of wire of total length 2.0 m is formed into a circular loop having 5.0 turns. If the wire carries a 1.2-A current, determine the magnitude of the magnetic field at the center of the loop.

Correct AnswerverifiedShow Answer

A long wire is known to have a radius greater than 4.0 mm and to carry a current uniformly distributed over its cross section. If the magnitude of the magnetic field is 0.285 mT at a point 4.0 mm from the axis of the wire and 0.200 mT at a point 10 mm from the axis, what is the radius of the wire?

Correct AnswerverifiedShow Answer

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

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The magnetic moment of an electron (charge = −e; mass = m_e) moving in a circular orbit of radius r with speed v about a nucleus of mass m_N is proportional to

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified