Question 1

If an electron has an orbital angular momentum with magnitude L the magnitude of the orbital contribution to its magnetic dipole moment is given by:

Accepted Answer

A) eL/m 
B) eL/2m 
C) 2eL/m 
D) mL/e 
E) mL/2 
A) eL/m 
B) eL/2m 
C) 2eL/m 
D) mL/e 
E) mL/2 B

Question 2

One of the crucial facts upon which the Maxwell equations are based is:

Accepted Answer

A) the numerical value of the electron charge 
B) charge is quantized 
C) the numerical value of the charge/mass ratio of the electron 
D) there are three types of magnetic materials 
E) none of the above 
A) the numerical value of the electron charge 
B) charge is quantized 
C) the numerical value of the charge/mass ratio of the electron 
D) there are three types of magnetic materials 
E) none of the above E

Question 3

The units of magnetization are:

Accepted Answer

A) ampere 
B) ampere.meter 
C) ampere.meter2 
D) ampere/meter 
E) ampere/meter2 
A) ampere 
B) ampere.meter 
C) ampere.meter2 
D) ampere/meter 
E) ampere/meter2 D

Question 4

The diagram shows one plate of a parallel-plate capacitor from within the capacitor.The plate is circular and has radius R.The dashed circles are four integration paths have radii of r1 = R/4, r2 = R/2, r3 =3 R/2, and r4 = 2R.Rank the paths according to the magnitude of around the paths during the discharging of the capacitor, least to greatest.

Accepted Answer

A) 1, 2 and 3 tie, then 4 
B) 1, 2, 3, 4 
C) 1, then 2 and 4 tie, then 3 
D) 4, 3, 1, 2 
E) 3, then 2 and 4 tie, then 1 
A) 1, 2 and 3 tie, then 4 
B) 1, 2, 3, 4 
C) 1, then 2 and 4 tie, then 3 
D) 4, 3, 1, 2 
E) 3, then 2 and 4 tie, then 1

Question 5

The magnetic field of Earth is roughly the same as that of a magnetic dipole with a dipole moment of about:

Accepted Answer

A) 1017 J/T 
B) 1019 J/T 
C) 1021 J/T 
D) 1023 J/T 
E) 1025 J/T 
A) 1017 J/T 
B) 1019 J/T 
C) 1021 J/T 
D) 1023 J/T 
E) 1025 J/T

Question 6

A bar magnet is broken in half.Each half is broken in half again, etc.The observation is that each piece has both a north and south pole.This is usually explained by:

Accepted Answer

A) Ampere's theory that all magnetic phenomena result from electric currents 
B) our inability to divide the magnet into small enough pieces 
C) Coulomb's law 
D) Lenz' law 
E) conservation of charge 
A) Ampere's theory that all magnetic phenomena result from electric currents 
B) our inability to divide the magnet into small enough pieces 
C) Coulomb's law 
D) Lenz' law 
E) conservation of charge

Question 7

If is the orbital angular momentum of an electron, the magnetic dipole moment associated with its orbital motion:

Accepted Answer

A) is in the direction of and has magnitude proportional to L 
B) is opposite to the direction of and has magnitude proportional to L 
C) is in the direction of and has magnitude proportional to L2 
D) is opposite to the direction of and has magnitude proportional to L2 
E) does not depend on 
A) is in the direction of and has magnitude proportional to L 
B) is opposite to the direction of and has magnitude proportional to L 
C) is in the direction of and has magnitude proportional to L2 
D) is opposite to the direction of and has magnitude proportional to L2 
E) does not depend on

Question 8

The diagram shows two small paramagnetic spheres, one near each end of a bar magnet.Which of the following statements is true?

Accepted Answer

A) The force on 1 is toward the magnet and the force on 2 is away from the magnet 
B) The force on 1 is away from the magnet and the force on 2 is away from the magnet 
C) The forces on 1 and 2 are both toward the magnet 
D) The forces on 1 and 2 are both away from the magnet 
E) The magnet does not exert a force on either sphere 
A) The force on 1 is toward the magnet and the force on 2 is away from the magnet 
B) The force on 1 is away from the magnet and the force on 2 is away from the magnet 
C) The forces on 1 and 2 are both toward the magnet 
D) The forces on 1 and 2 are both away from the magnet 
E) The magnet does not exert a force on either sphere

Question 9

The magnitude of the Bohr magneton is about:

Accepted Answer

A) 10-15 J/T 
B) 10-19 J/T 
C) 10-23 J/T 
D) 10-27 J/T 
E) 10-31 J/T 
A) 10-15 J/T 
B) 10-19 J/T 
C) 10-23 J/T 
D) 10-27 J/T 
E) 10-31 J/T

Question 10

The behavior of ferromagnetic domains in an applied magnetic field gives rise to:

Accepted Answer

A) hysteresis 
B) ferromagnetism 
C) the Curie law 
D) a lowering of the Curie temperature 
E) Gauss' law for magnetism 
A) hysteresis 
B) ferromagnetism 
C) the Curie law 
D) a lowering of the Curie temperature 
E) Gauss' law for magnetism

Question 11

The potential energy of a magnetic dipole in an external magnetic field is least when:

Accepted Answer

A) the dipole moment is parallel to the field 
B) the dipole moment is antiparallel to the field 
C) the dipole moment is perpendicular to the field 
D) none of the above (the same energy is associated with all orientations) 
E) none of the above (no energy is associated with the dipole-field interaction) 
A) the dipole moment is parallel to the field 
B) the dipole moment is antiparallel to the field 
C) the dipole moment is perpendicular to the field 
D) none of the above (the same energy is associated with all orientations) 
E) none of the above (no energy is associated with the dipole-field interaction)

Question 12

Of the following places one would expect that the horizontal component of the Earth's magnetic field to be largest in:

Accepted Answer

A) Maine 
B) Florida 
C) Maryland 
D) New York 
E) Iowa 
A) Maine 
B) Florida 
C) Maryland 
D) New York 
E) Iowa

Question 13

The diagram shows the spin angular momentum vectors of two electrons and two protons in the same external magnetic field.The field points upward in the diagram.Rank the situations according to the potential energy, least to greatest.

Accepted Answer

A) 1 and 3 tie, then 2 and 4 tie 
B) 2 and 3 tie, then 1 and 4 tie 
C) 1 and 2 tie, then 3 and 4 tie 
D) 3 and 4 tie, then 1 and 2 tie 
E) all tie 
A) 1 and 3 tie, then 2 and 4 tie 
B) 2 and 3 tie, then 1 and 4 tie 
C) 1 and 2 tie, then 3 and 4 tie 
D) 3 and 4 tie, then 1 and 2 tie 
E) all tie

Question 14

Magnetization vectors in neighboring ferromagnetic domains are:

Accepted Answer

A) always in opposite directions 
B) always in the same direction 
C) always in different directions 
D) sometimes in different directions and sometimes in the same direction 
E) sometimes in opposite directions and sometimes in the same direction 
A) always in opposite directions 
B) always in the same direction 
C) always in different directions 
D) sometimes in different directions and sometimes in the same direction 
E) sometimes in opposite directions and sometimes in the same direction

Question 15

Four closed surfaces are shown, each with circular top and bottom faces and curved sides.The areas Atop and Abot of the top and bottom faces and the magnitudes Btop and Bbot of the uniform magnetic fields through the top and bottom faces are given.The fields are perpendicular to the faces and are either inward or outward.Rank the surfaces according to the magnitude of the magnetic flux through the curved sides, least to greatest.

Accepted Answer

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

Question 16

An electron in a hydrogen atom moves in a circle of radius 1.1 x 10-10 m at a speed of about 1.6 x 106 m/s.What is the magnetic dipole moment of this electron due to its orbital motion?

Accepted Answer

A) 9.3 x 10-24 J/T 
B) 1.4 x 10-23 J/T 
C) 1.9 x 10-23 J/T 
D) 2.8 x 10-23 J/T 
E) 3.5 x 10-23 J/T 
A) 9.3 x 10-24 J/T 
B) 1.4 x 10-23 J/T 
C) 1.9 x 10-23 J/T 
D) 2.8 x 10-23 J/T 
E) 3.5 x 10-23 J/T

Question 17

One of the Maxwell equations begins with ....The symbol means:

Accepted Answer

A) an infinitesimal displacement of a charge 
B) an infinitesimal displacement of a magnetic pole 
C) an infinitesimal inductance 
D) an infinitesimal surface area 
E) none of the above 
A) an infinitesimal displacement of a charge 
B) an infinitesimal displacement of a magnetic pole 
C) an infinitesimal inductance 
D) an infinitesimal surface area 
E) none of the above

Question 18

A magnetic field parallel to the x axis with a magnitude that decreases with increasing x but does not change with y and z is impossible according to:

Accepted Answer

A) Faraday's law 
B) Ampere's law 
C) Gauss' law for electricity 
D) Gauss' law for magnetism 
E) Newton's second law 
A) Faraday's law 
B) Ampere's law 
C) Gauss' law for electricity 
D) Gauss' law for magnetism 
E) Newton's second law

Question 19

A 1.2-m radius cylindrical region contains a uniform electric field along the cylinder axis.It is increasing uniformly with time.To obtain a total displacement current of 2.0* 10 - 9 A through a cross section of the region, the magnitude of the electric field should change at a rate of:

Accepted Answer

A) 5.0 V/m·s 
B) 12 V/m·s 
C) 37 V/m·s 
D) 50 V/m·s 
E) 4.0 * 107 V/m·s 
A) 5.0 V/m·s 
B) 12 V/m·s 
C) 37 V/m·s 
D) 50 V/m·s 
E) 4.0 * 107 V/m·s

Question 20

A cylindrical region contains a uniform electric field that is along the cylinder axis and is changing with time.If r is the distance from the cylinder axis the magnitude of the magnetic field within the region is:

Accepted Answer

A) uniform 
B) proportional to 1/r 
C) proportional to r2 
D) proportional to 1/r2 
E) proportional to r 
A) uniform 
B) proportional to 1/r 
C) proportional to r2 
D) proportional to 1/r2 
E) proportional to r

Exam 32: Maxwells Equations; Magnetism of Matter

If an electron has an orbital angular momentum with magnitude L the magnitude of the orbital contribution to its magnetic dipole moment is given by:

One of the crucial facts upon which the Maxwell equations are based is:

The units of magnetization are:

The magnetic field of Earth is roughly the same as that of a magnetic dipole with a dipole moment of about:

A bar magnet is broken in half.Each half is broken in half again, etc.The observation is that each piece has both a north and south pole.This is usually explained by:

If is the orbital angular momentum of an electron, the magnetic dipole moment associated with its orbital motion:

The diagram shows two small paramagnetic spheres, one near each end of a bar magnet.Which of the following statements is true?

The magnitude of the Bohr magneton is about:

The behavior of ferromagnetic domains in an applied magnetic field gives rise to:

The potential energy of a magnetic dipole in an external magnetic field is least when:

Of the following places one would expect that the horizontal component of the Earth's magnetic field to be largest in:

The diagram shows the spin angular momentum vectors of two electrons and two protons in the same external magnetic field.The field points upward in the diagram.Rank the situations according to the potential energy, least to greatest.

Magnetization vectors in neighboring ferromagnetic domains are:

An electron in a hydrogen atom moves in a circle of radius 1.1 x 10-10 m at a speed of about 1.6 x 106 m/s.What is the magnetic dipole moment of this electron due to its orbital motion?

One of the Maxwell equations begins with ....The symbol means:

A magnetic field parallel to the x axis with a magnitude that decreases with increasing x but does not change with y and z is impossible according to:

A 1.2-m radius cylindrical region contains a uniform electric field along the cylinder axis.It is increasing uniformly with time.To obtain a total displacement current of 2.0* 10 - 9 A through a cross section of the region, the magnitude of the electric field should change at a rate of:

A cylindrical region contains a uniform electric field that is along the cylinder axis and is changing with time.If r is the distance from the cylinder axis the magnitude of the magnetic field within the region is:

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An electron in a hydrogen atom moves in a circle of radius 1.1 x 10^-1⁰ m at a speed of about 1.6 x 10⁶ m/s.What is the magnetic dipole moment of this electron due to its orbital motion?

A 1.2-m radius cylindrical region contains a uniform electric field along the cylinder axis.It is increasing uniformly with time.To obtain a total displacement current of 2.0* 10 ^- ⁹A through a cross section of the region, the magnitude of the electric field should change at a rate of: