Question 1

The soft iron core in the solenoid shown is removable. Then:

Accepted Answer

A)  the current will be larger without the core 
B)  the current will be larger with the core 
C)  one must do work to remove the core 
D)  the circuit will do work in expelling the core 
E)  the stored energy is the same with or without the core 
A)  the current will be larger without the core 
B)  the current will be larger with the core 
C)  one must do work to remove the core 
D)  the circuit will do work in expelling the core 
E)  the stored energy is the same with or without the core C

Question 2

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right. The directions of the infinitesimal path element and infinitesimal area element are:

Accepted Answer

A)  always in the same direction 
B)  always in opposite directions 
C)  always perpendicular to each other 
D)  never perpendicular to each other 
E)  none of the above 
A)  always in the same direction 
B)  always in opposite directions 
C)  always perpendicular to each other 
D)  never perpendicular to each other 
E)  none of the above E

Question 3

Suppose you are looking into one end of a long cylindrical tube in which there is a uniform electric field, pointing away from you. If the magnitude of the field is decreasing with time the field lines of the induced magnetic field are:

Accepted Answer

A)  circles 
B)  ellipses 
C)  straight lines parallel to the electric field 
D)  straight lines perpendicular to the electric field 
E)  none of the above 
A)  circles 
B)  ellipses 
C)  straight lines parallel to the electric field 
D)  straight lines perpendicular to the electric field 
E)  none of the above A

Question 4

When a permanent magnet is strongly heated:

Accepted Answer

A)  nothing happens 
B)  it becomes an induced magnet 
C)  it loses its magnetism 
D)  its magnetism increases 
E)  its polarity reverses 
A)  nothing happens 
B)  it becomes an induced magnet 
C)  it loses its magnetism 
D)  its magnetism increases 
E)  its polarity reverses

Question 5

Magnetization is:

Accepted Answer

A)  the current density in an object 
B)  the charge density of moving charges in an object 
C)  the magnetic dipole moment of an object 
D)  the magnetic dipole moment per unit volume of an object 
E)  the magnetic field per unit volume produced by an object 
A)  the current density in an object 
B)  the charge density of moving charges in an object 
C)  the magnetic dipole moment of an object 
D)  the magnetic dipole moment per unit volume of an object 
E)  the magnetic field per unit volume produced by an object

Question 6

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

Question 7

A 1-$\mu$F capacitor is connected to an emf that is increasing uniformly with time at a rate of 100 V/s. The displacement current between the plates is:

Accepted Answer

A)  0 A 
B)  1 * 10-8 A 
C)  1 *10-6 A 
D)  1 * 10-4 A 
E)  100 A 
A)  0 A 
B)  1 * 10-8 A 
C)  1 *10-6 A 
D)  1 * 10-4 A 
E)  100 A

Question 8

A bar magnet is placed vertically with its S pole up and its N pole down. The field at its center is:

Accepted Answer

A)  zero 
B)  down 
C)  up 
D)  horizontal 
E)  slightly below the horizontal 
A)  zero 
B)  down 
C)  up 
D)  horizontal 
E)  slightly below the horizontal

Question 9

Consider the four Maxwell equations:   Which of these must be modified if magnetic poles are discovered?

Accepted Answer

A)  only I 
B)  only II 
C)  only II and III 
D)  only III and IV 
E)  only II, III, IV 
A)  only I 
B)  only II 
C)  only II and III 
D)  only III and IV 
E)  only II, III, IV

Question 10

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 11

What are the possible allowed values of the spin magnetic quantum number ms of the electron?

Accepted Answer

A)  +1/2 only 
B)  ±1/2 
C)  any half-odd integer 
D)  any integer 
E)  It depends on the external magnetic field. 
A)  +1/2 only 
B)  ±1/2 
C)  any half-odd integer 
D)  any integer 
E)  It depends on the external magnetic field.

Question 12

Because ferromagnets exhibit hysteresis, the magnetization:

Accepted Answer

A)  can never be in the same direction as an applied field 
B)  may not vanish when an applied field is reduced to zero 
C)  can never vanish 
D)  is proportional to any applied magnetic field 
E)  is always opposite to the direction of any applied magnetic field 
A)  can never be in the same direction as an applied field 
B)  may not vanish when an applied field is reduced to zero 
C)  can never vanish 
D)  is proportional to any applied magnetic field 
E)  is always opposite to the direction of any applied magnetic field

Question 13

The magnetic dipole moment of an atomic electron is typically:

Accepted Answer

A)  much less than a Bohr magneton 
B)  a few Bohr magnetons 
C)  much greater than a Bohr magneton 
D)  much greater or much less than a Bohr magneton, depending on the atom 
E)  not related to the value of the Bohr magneton 
A)  much less than a Bohr magneton 
B)  a few Bohr magnetons 
C)  much greater than a Bohr magneton 
D)  much greater or much less than a Bohr magneton, depending on the atom 
E)  not related to the value of the Bohr magneton

Question 14

A 1-A current is used to charge a parallel plate capacitor. A large square piece of paper is placed between the plates and parallel to them so it sticks out on all sides. The value of the integral around the perimeter of the paper is:

Accepted Answer

A)  2 T.m 
B)  4 $\pi$*10-7 T.m 
C)  8.85 * 10-12 T.m 
D)  10-7 T.m 
E)  not determined from the given quantities 
A)  2 T.m 
B)  4 $\pi$*10-7 T.m 
C)  8.85 * 10-12 T.m 
D)  10-7 T.m 
E)  not determined from the given quantities

Question 15

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 16

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 17

Of the three chief kinds of magnetic materials (diamagnetic, paramagnetic, and ferromagnetic) which are used to make permanent magnets?

Accepted Answer

A)  only diamagnetic 
B)  only ferromagnetic 
C)  only paramagnetic 
D)  only paramagnetic and ferromagnetic 
E)  all three 
A)  only diamagnetic 
B)  only ferromagnetic 
C)  only paramagnetic 
D)  only paramagnetic and ferromagnetic 
E)  all three

Question 18

The statement that magnetic field lines form closed loops is a direct consequence of:

Accepted Answer

A)  Faraday's law 
B)  Ampere's law 
C)  Gauss' law for electricity 
D)  Gauss' law for magnetism 
E)  the Lorentz force 
A)  Faraday's law 
B)  Ampere's law 
C)  Gauss' law for electricity 
D)  Gauss' law for magnetism 
E)  the Lorentz force

Question 19

Ferromagnetism is closely associated with:

Accepted Answer

A)  the tendency of electron dipole moments to align with an applied magnetic field 
B)  the tendency of electron dipole moments to align opposite to an applied magnetic field 
C)  the tendency of electron dipole moments to change magnitude in an applied magnetic field 
D)  the tendency of electron dipole moments to align with each other 
E)  the force exerted by electron dipole moments on each other 
A)  the tendency of electron dipole moments to align with an applied magnetic field 
B)  the tendency of electron dipole moments to align opposite to an applied magnetic field 
C)  the tendency of electron dipole moments to change magnitude in an applied magnetic field 
D)  the tendency of electron dipole moments to align with each other 
E)  the force exerted by electron dipole moments on each other

Question 20

Magnetic dipole X is fixed and dipole Y is free to move. Dipole Y will initially:

Accepted Answer

A)  move toward X but not rotate 
B)  move away from X but not rotate 
C)  move toward X and rotate 
D)  move away from X and rotate 
E)  rotate but not translate 
A)  move toward X but not rotate 
B)  move away from X but not rotate 
C)  move toward X and rotate 
D)  move away from X and rotate 
E)  rotate but not translate

Exam 32: Maxwells Equations; Magnetism of Matter

The soft iron core in the solenoid shown is removable. Then:

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right. The directions of the infinitesimal path element and infinitesimal area element are:

Suppose you are looking into one end of a long cylindrical tube in which there is a uniform electric field, pointing away from you. If the magnitude of the field is decreasing with time the field lines of the induced magnetic field are:

When a permanent magnet is strongly heated:

Magnetization is:

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:

A 1- μ\muμ F capacitor is connected to an emf that is increasing uniformly with time at a rate of 100 V/s. The displacement current between the plates is:

A bar magnet is placed vertically with its S pole up and its N pole down. The field at its center is:

Consider the four Maxwell equations: Which of these must be modified if magnetic poles are discovered?

What are the possible allowed values of the spin magnetic quantum number ms of the electron?

Because ferromagnets exhibit hysteresis, the magnetization:

The magnetic dipole moment of an atomic electron is typically:

A 1-A current is used to charge a parallel plate capacitor. A large square piece of paper is placed between the plates and parallel to them so it sticks out on all sides. The value of the integral around the perimeter of the paper is:

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 three chief kinds of magnetic materials (diamagnetic, paramagnetic, and ferromagnetic) which are used to make permanent magnets?

The statement that magnetic field lines form closed loops is a direct consequence of:

Ferromagnetism is closely associated with:

Magnetic dipole X is fixed and dipole Y is free to move. Dipole Y will initially:

Measurement

Motion Along a Straight Line

Vector

Motion in Two and Three Dimensions

Force and Motion I

Force and Motion II

Kinetic Energy and Work

Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

Rolling, Torque, and Angular Momentum

Equilibrium and Elasticity

Gravitation

Fluids

Oscillations

Waves I

Waves II

Temperature, Heat, and the First Law of Thermodynamics

The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

Electric Charge

Electric Fields

Gauss Law

Electric Potential

Capacitance

Current and Resistance

Circuits

Magnetic Fields

Magnetic Fields Due to Currents

Induction and Inductance

Electromagnetic Oscillations and Alternating Current

Electromagnetic Waves

Images

Interference

Diffraction

Relativity

Photons and Matter Waves

More About Matter Waves

All About Atoms

Conduction of Electricity in Solids

Nuclear Physics

Energy From the Nucleus

Quarks, Leptons, and the Big Bang

Filters

A 1- $\mu$ F capacitor is connected to an emf that is increasing uniformly with time at a rate of 100 V/s. The displacement current between the plates is:

What are the possible allowed values of the spin magnetic quantum number m_s of the electron?