Question 1

If m = mB (in a paramagnetic material) for an external magnetic field of 20 kG, what fraction of the saturation magnetization is M at 400 K?

Accepted Answer

A)  5.60 * 10-4  
B)  2.24 *10-3  
C)  1.12 * 10-3  
D)  3.36 * 10-3  
E)  4.48 * 10-1  
A)  5.60 * 10-4  
B)  2.24 *10-3  
C)  1.12 * 10-3  
D)  3.36 * 10-3  
E)  4.48 * 10-1

Question 2

A tightly wound solenoid is 15 cm long, has 350 turns, carries a current of 3.0 A, and has an aluminum core ($\chi$m = 2.3 * 10-5). If you ignore end effects, you will find that the value of the magnetization M at the center is approximately

Accepted Answer

A)  16 mA/m 
B)  8.8 mA/m 
C)  1.8 mA/m 
D)  24 mA/m 
E)  6.2 mA/m 
A)  16 mA/m 
B)  8.8 mA/m 
C)  1.8 mA/m 
D)  24 mA/m 
E)  6.2 mA/m

Question 3

A long cylindrical bar magnet has a magnetization M = 3000 A/m. What is the equivalent current on the curved surface of the cylinder for 5 cm length of the magnet?

Accepted Answer

A)  10 A 
B)  15 A 
C)  100 A 
D)  150 A 
E)  None of these is correct. 
A)  10 A 
B)  15 A 
C)  100 A 
D)  150 A 
E)  None of these is correct.

Question 4

A point charge of q1 = 3.6 nC is moving with speed 4.5 * 107 m/s parallel to the y axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, y = 4 m is approximately

Accepted Answer

A)  0.39 nT   
B)  -0.78 nT   
C)  -0.39 nT   
D)  0.78 nT   
E)  2.0 nT   
A)  0.39 nT   
B)  -0.78 nT   
C)  -0.39 nT   
D)  0.78 nT   
E)  2.0 nT

Question 5

A long solenoid of radius 3 cm has 1100 turns per m. If the solenoid wire carries a current of 1.5 A, then calculate the magnetic field inside the solenoid.

Accepted Answer

A)  2.1 * 10-3 T 
B)  1.0 *10-3 T 
C)  1.7 *10-4 T 
D)  7.0 *10-2 T 
E)  none of the above 
A)  2.1 * 10-3 T 
B)  1.0 *10-3 T 
C)  1.7 *10-4 T 
D)  7.0 *10-2 T 
E)  none of the above

Question 6

You place a substance in an external magnetic field and find that it is attracted to the field but only to a limited degree because of thermal agitation effects which do not permit atomic dipoles to align completely with the field. You know, therefore, that this substance is

Accepted Answer

A)  diamagnetic 
B)  paramagnetic 
C)  permamagnetic 
D)  ferromagnetic 
E)  antimagnetic 
A)  diamagnetic 
B)  paramagnetic 
C)  permamagnetic 
D)  ferromagnetic 
E)  antimagnetic

Question 7

The magnetic field at point P, due to the current in the very long wire, varies with distance R according to

Accepted Answer

A)  R2  
B)  R-3  
C)  R-2  
D)  R3  
E)  R-1  
A)  R2  
B)  R-3  
C)  R-2  
D)  R3  
E)  R-1

Question 8

A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The applied field   app is approximately

Accepted Answer

A)  1.88 mT 
B)  3.77 mT 
C)  4.32 mT 
D)  3.87 mT 
E)  1.93 mT 
A)  1.88 mT 
B)  3.77 mT 
C)  4.32 mT 
D)  3.87 mT 
E)  1.93 mT

Question 9

Two parallel wires carry currents I1 and I2 = 2I1 in the same direction. Which of the following expressions shows the relationship of the forces on the wires?

Accepted Answer

A)  F1 = F2  
B)  F1 = 2F2  
C)  2F1 = F2  
D)  F1 = 4F2  
E)  4F1 = F2  
A)  F1 = F2  
B)  F1 = 2F2  
C)  2F1 = F2  
D)  F1 = 4F2  
E)  4F1 = F2

Question 10

A point charge of q1 = 5.8 nC is moving with speed 2.5 * 107 m/s parallel to the z axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, z = 4 m is approximately

Accepted Answer

A)  0.70 nT   
B)  -0.70 nT   
C)  3.2 nT   
D)  -1.6 nT   
E)  -0.35 nT   
A)  0.70 nT   
B)  -0.70 nT   
C)  3.2 nT   
D)  -1.6 nT   
E)  -0.35 nT

Question 11

A coaxial cable consists of a solid inner cylindrical conductor of radius 2 mm and an outer cylindrical shell of inner radius 3 mm and outer radius 3.5 mm. A current of 15 A flows down the inner wire and an equal return current flows in the outer conductor. If we assume that the currents are uniform over the cross section of the conductors, then calculate the magnitude of the enclosed current for use in Ampere's Law at a radius of 3.25 mm.

Accepted Answer

A)  7.2 A 
B)  3.8 A 
C)  7.8 A 
D)  11.2 A 
E)  7.5 A 
A)  7.2 A 
B)  3.8 A 
C)  7.8 A 
D)  11.2 A 
E)  7.5 A

Question 12

What is the magnetic field at the center of a circular loop with a diameter of 15.0 cm that carries a current of 1.50 A?

Accepted Answer

A)  zero 
B)  6.28 *10-6 T 
C)  1.26 * 10-5 T 
D)  2.51* 10-5 T 
E)  1.68* 10-4 T 
A)  zero 
B)  6.28 *10-6 T 
C)  1.26 * 10-5 T 
D)  2.51* 10-5 T 
E)  1.68* 10-4 T

Question 13

A tightly wound solenoid is 15 cm long, has 350 turns, carries a current of 3.0 A, and has an aluminum core ($\chi$m = 2.3 *10-5). If you ignore end effects, you will find that the value of   at the center is approximately

Accepted Answer

A)  11 mT 
B)  8.8 mT 
C)  1.8 mT 
D)  7.0 mT 
E)  6.2 mT 
A)  11 mT 
B)  8.8 mT 
C)  1.8 mT 
D)  7.0 mT 
E)  6.2 mT

Question 14

A cylindrical bar magnet of radius 1.00 cm and length 10.0 cm has a magnetic dipole moment of magnitude m = 2.00 A · m2. What is the magnetization M, assuming it to be uniform in the magnet?

Accepted Answer

A)  2.53* 104 A/m 
B)  6.37 * 104 A/m 
C)  3.18 * 104 A/m 
D)  1.86 * 104 A/m 
E)  3.18* 102 A/m 
A)  2.53* 104 A/m 
B)  6.37 * 104 A/m 
C)  3.18 * 104 A/m 
D)  1.86 * 104 A/m 
E)  3.18* 102 A/m

Question 15

Two very long, parallel conducting wires carry equal currents in the same direction, as shown. The numbered diagrams show end views of the wires and the resultant force vectors due to current flow in each wire. Which diagram best represents the direction of the forces?

Accepted Answer

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

Question 16

An electron beam travels counterclockwise in a circle of radius R in the magnetic field produced by the Helmholtz coils as shown. If you increase the current in the Helmholtz coils, the electron beam will

Accepted Answer

A)  increase its radius. 
B)  decrease its radius. 
C)  maintain the same radius. 
D)  reverse and travel clockwise with the same radius. 
E)  reverse and travel clockwise with a larger radius. 
A)  increase its radius. 
B)  decrease its radius. 
C)  maintain the same radius. 
D)  reverse and travel clockwise with the same radius. 
E)  reverse and travel clockwise with a larger radius.

Question 17

At the instant the positively charged body is at the origin, the magnetic field at point P due to the motion of this charged body 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. 
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 18

Which of the following statements is false?

Accepted Answer

A)  When an electric field is applied to a dielectric, the resultant electric field always decreases. 
B)  When a magnetic field is applied to a paramagnetic material, the resultant magnetic field always increases. 
C)  When a magnetic field is applied to a diamagnetic material, the resultant magnetic field always decreases. 
D)  When a magnetic field is applied to a ferromagnetic material, the resultant magnetic field always increases. 
E)  A magnetic dipole can line up parallel or anti-parallel to an applied magnetic field. 
A)  When an electric field is applied to a dielectric, the resultant electric field always decreases. 
B)  When a magnetic field is applied to a paramagnetic material, the resultant magnetic field always increases. 
C)  When a magnetic field is applied to a diamagnetic material, the resultant magnetic field always decreases. 
D)  When a magnetic field is applied to a ferromagnetic material, the resultant magnetic field always increases. 
E)  A magnetic dipole can line up parallel or anti-parallel to an applied magnetic field.

Question 19

A tightly wound solenoid is 15 cm long, has 350 turns, and carries a current of 3.0 A. If you ignore end effects, you will find that the value of   app at the center of the solenoid when there is no core is approximately

Accepted Answer

A)  3.6 mT 
B)  44 $\mu$T 
C)  4.4 mT 
D)  88 $\mu$T 
E)  8.8 mT 
A)  3.6 mT 
B)  44 $\mu$T 
C)  4.4 mT 
D)  88 $\mu$T 
E)  8.8 mT

Question 20

Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I, each in opposite directions. If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods, then calculate the current I.

Accepted Answer

A)  160 A 
B)  18 A 
C)  13 A 
D)  3.6 A 
E)  9.0 A 
A)  160 A 
B)  18 A 
C)  13 A 
D)  3.6 A 
E)  9.0 A

If m = m_B (in a paramagnetic material) for an external magnetic field of 20 kG, what fraction of the saturation magnetization is M at 400 K?

A tightly wound solenoid is 15 cm long, has 350 turns, carries a current of 3.0 A, and has an aluminum core ( $\chi$ _m = 2.3 * 10^-5). If you ignore end effects, you will find that the value of the magnetization M at the center is approximately

A long cylindrical bar magnet has a magnetization M = 3000 A/m. What is the equivalent current on the curved surface of the cylinder for 5 cm length of the magnet?

A point charge of q₁ = 3.6 nC is moving with speed 4.5 * 10⁷ m/s parallel to the y axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, y = 4 m is approximately

A long solenoid of radius 3 cm has 1100 turns per m. If the solenoid wire carries a current of 1.5 A, then calculate the magnetic field inside the solenoid.

You place a substance in an external magnetic field and find that it is attracted to the field but only to a limited degree because of thermal agitation effects which do not permit atomic dipoles to align completely with the field. You know, therefore, that this substance is

The magnetic field at point P, due to the current in the very long wire, varies with distance R according to

A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The applied field _app is approximately

Two parallel wires carry currents I₁ and I₂ = 2I₁ in the same direction. Which of the following expressions shows the relationship of the forces on the wires?

A point charge of q₁ = 5.8 nC is moving with speed 2.5 * 10⁷ m/s parallel to the z axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, z = 4 m is approximately

What is the magnetic field at the center of a circular loop with a diameter of 15.0 cm that carries a current of 1.50 A?

A cylindrical bar magnet of radius 1.00 cm and length 10.0 cm has a magnetic dipole moment of magnitude m = 2.00 A · m². What is the magnetization M, assuming it to be uniform in the magnet?

Two very long, parallel conducting wires carry equal currents in the same direction, as shown. The numbered diagrams show end views of the wires and the resultant force vectors due to current flow in each wire. Which diagram best represents the direction of the forces?

An electron beam travels counterclockwise in a circle of radius R in the magnetic field produced by the Helmholtz coils as shown. If you increase the current in the Helmholtz coils, the electron beam will

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

Which of the following statements is false?

A tightly wound solenoid is 15 cm long, has 350 turns, and carries a current of 3.0 A. If you ignore end effects, you will find that the value of _app at the center of the solenoid when there is no core is approximately

Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I, each in opposite directions. If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods, then calculate the current I.

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

Exam 7: Sources of the Magnetic Field

If m = mB (in a paramagnetic material) for an external magnetic field of 20 kG, what fraction of the saturation magnetization is M at 400 K?

A tightly wound solenoid is 15 cm long, has 350 turns, carries a current of 3.0 A, and has an aluminum core ( χ\chiχ m = 2.3 * 10-5). If you ignore end effects, you will find that the value of the magnetization M at the center is approximately

A long cylindrical bar magnet has a magnetization M = 3000 A/m. What is the equivalent current on the curved surface of the cylinder for 5 cm length of the magnet?

A point charge of q1 = 3.6 nC is moving with speed 4.5 * 107 m/s parallel to the y axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, y = 4 m is approximately

A long solenoid of radius 3 cm has 1100 turns per m. If the solenoid wire carries a current of 1.5 A, then calculate the magnetic field inside the solenoid.

You place a substance in an external magnetic field and find that it is attracted to the field but only to a limited degree because of thermal agitation effects which do not permit atomic dipoles to align completely with the field. You know, therefore, that this substance is

The magnetic field at point P, due to the current in the very long wire, varies with distance R according to

A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The applied field app is approximately

Two parallel wires carry currents I1 and I2 = 2I1 in the same direction. Which of the following expressions shows the relationship of the forces on the wires?

A point charge of q1 = 5.8 nC is moving with speed 2.5 * 107 m/s parallel to the z axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, z = 4 m is approximately

What is the magnetic field at the center of a circular loop with a diameter of 15.0 cm that carries a current of 1.50 A?

A tightly wound solenoid is 15 cm long, has 350 turns, carries a current of 3.0 A, and has an aluminum core ( χ\chiχ m = 2.3 *10-5). If you ignore end effects, you will find that the value of at the center is approximately

A cylindrical bar magnet of radius 1.00 cm and length 10.0 cm has a magnetic dipole moment of magnitude m = 2.00 A · m2. What is the magnetization M, assuming it to be uniform in the magnet?

Two very long, parallel conducting wires carry equal currents in the same direction, as shown. The numbered diagrams show end views of the wires and the resultant force vectors due to current flow in each wire. Which diagram best represents the direction of the forces?

An electron beam travels counterclockwise in a circle of radius R in the magnetic field produced by the Helmholtz coils as shown. If you increase the current in the Helmholtz coils, the electron beam will

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

Which of the following statements is false?

A tightly wound solenoid is 15 cm long, has 350 turns, and carries a current of 3.0 A. If you ignore end effects, you will find that the value of app at the center of the solenoid when there is no core is approximately

Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I, each in opposite directions. If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods, then calculate the current I.

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

If m = m_B (in a paramagnetic material) for an external magnetic field of 20 kG, what fraction of the saturation magnetization is M at 400 K?

A tightly wound solenoid is 15 cm long, has 350 turns, carries a current of 3.0 A, and has an aluminum core ( $\chi$ _m = 2.3 * 10^-5). If you ignore end effects, you will find that the value of the magnetization M at the center is approximately

A point charge of q₁ = 3.6 nC is moving with speed 4.5 * 10⁷ m/s parallel to the y axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, y = 4 m is approximately

A long solenoid with 20 turns per centimeter has a core of iron-silicon. When the current is 1.50 A, the magnetic field inside the core is 4.50 T. The applied field _app is approximately

Two parallel wires carry currents I₁ and I₂ = 2I₁ in the same direction. Which of the following expressions shows the relationship of the forces on the wires?

A point charge of q₁ = 5.8 nC is moving with speed 2.5 * 10⁷ m/s parallel to the z axis along the line x = 3 m. The magnetic field produced by this charge at the origin when it is at the point x = 3 m, z = 4 m is approximately

A cylindrical bar magnet of radius 1.00 cm and length 10.0 cm has a magnetic dipole moment of magnitude m = 2.00 A · m². What is the magnetization M, assuming it to be uniform in the magnet?

A tightly wound solenoid is 15 cm long, has 350 turns, and carries a current of 3.0 A. If you ignore end effects, you will find that the value of _app at the center of the solenoid when there is no core is approximately