Question 1

A small bar magnet is suspended horizontally by a string.When placed in a uniform horizontal magnetic field, it will:

Accepted Answer

A) translate in the direction of 
B) translate in the opposite direction of 
C) rotate so as to be at right angles to 
D) rotate so as to be vertical 
E) none of the above 
A) translate in the direction of 
B) translate in the opposite direction of 
C) rotate so as to be at right angles to 
D) rotate so as to be vertical 
E) none of the above

Question 2

A sinusoidal emf is connected to a parallel plate capacitor.The magnetic field between the plates is:

Accepted Answer

A) zero 
B) constant 
C) sinusoidal and its amplitude does not depend on the frequency of the source 
D) sinusoidal and its amplitude is proportional to the frequency of the source 
E) sinusoidal and its amplitude is inversely proportional to the frequency of the source 
A) zero 
B) constant 
C) sinusoidal and its amplitude does not depend on the frequency of the source 
D) sinusoidal and its amplitude is proportional to the frequency of the source 
E) sinusoidal and its amplitude is inversely proportional to the frequency of the source

Question 3

Which of the following statements is correct?

Accepted Answer

A) The spin angular momentum of the electron can be directly observed, but the spin magnetic dipole moment cannot be. 
B) The spin angular momentum of the electron cannot be directly observed, but the spin magnetic dipole moment can be. 
C) Both the spin angular momentum and the spin magnetic dipole moment of the electron can be directly observed. 
D) Neither the spin angular momentum nor the spin magnetic dipole moment of the electron can be directly observed. 
E) Although both the spin angular momentum and the spin magnetic dipole moment can be defined theoretically, neither has any physical meaning at all. 
A) The spin angular momentum of the electron can be directly observed, but the spin magnetic dipole moment cannot be. 
B) The spin angular momentum of the electron cannot be directly observed, but the spin magnetic dipole moment can be. 
C) Both the spin angular momentum and the spin magnetic dipole moment of the electron can be directly observed. 
D) Neither the spin angular momentum nor the spin magnetic dipole moment of the electron can be directly observed. 
E) Although both the spin angular momentum and the spin magnetic dipole moment can be defined theoretically, neither has any physical meaning at all.

Question 4

The intrinsic magnetic dipole moments of protons and neutrons are much less than that of an electron because:

Accepted Answer

A) their masses are greater 
B) their angular momenta are much less 
C) their angular momenta are much greater 
D) their charges are much less 
E) their radii are much less 
A) their masses are greater 
B) their angular momenta are much less 
C) their angular momenta are much greater 
D) their charges are much less 
E) their radii are much less

Question 5

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 6

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 7

One of the Maxwell equations begins with ....The o symbol in the integral sign means:

Accepted Answer

A) the same as the subscript in $\mu$0 
B) integrate clockwise around the path 
C) integrate counterclockwise around the path 
D) integrate around a closed path 
E) integrate over a closed surface 
A) the same as the subscript in $\mu$0 
B) integrate clockwise around the path 
C) integrate counterclockwise around the path 
D) integrate around a closed path 
E) integrate over a closed surface

Question 8

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 9

A magnetic field exists between the plates of a capacitor:

Accepted Answer

A) always 
B) never 
C) when the capacitor is fully charged 
D) while the capacitor is being charged 
E) only when the capacitor is starting to be charged 
A) always 
B) never 
C) when the capacitor is fully charged 
D) while the capacitor is being charged 
E) only when the capacitor is starting to be charged

Question 10

An unmagnetized steel bar is placed inside a solenoid.As the current in the solenoid is slowly increased from zero to some large value, the magnetization of the bar:

Accepted Answer

A) increases proportionally with the current 
B) remains zero for a while and then increases linearly with any further increase in current 
C) increases with increasing current at first but later is much less affected by it 
D) is unaffected by the current 
E) increases quadratically with the current 
A) increases proportionally with the current 
B) remains zero for a while and then increases linearly with any further increase in current 
C) increases with increasing current at first but later is much less affected by it 
D) is unaffected by the current 
E) increases quadratically with the current

Question 11

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right.For them:

Accepted Answer

A) the path must pierce the area 
B) the path must be well-separated from the area 
C) the path must be along a field line and the area must be perpendicular to the field line 
D) the path must be the boundary of the area 
E) the path must lie in the area, away from its boundary 
A) the path must pierce the area 
B) the path must be well-separated from the area 
C) the path must be along a field line and the area must be perpendicular to the field line 
D) the path must be the boundary of the area 
E) the path must lie in the area, away from its boundary

Question 12

A magnetic field is applied to a paramagnetic substance.In the interior the magnetic field produced by the magnetic dipoles of the substance is:

Accepted Answer

A) greater than and in the opposite direction 
B) less than and in the opposite direction 
C) greater than and in the same direction 
D) less than and in the same direction 
E) the same as 
A) greater than and in the opposite direction 
B) less than and in the opposite direction 
C) greater than and in the same direction 
D) less than and in the same direction 
E) the same as

Question 13

An electron is on the z axis moving toward the xy plane but it has not reached that plane yet.At that instant:

Accepted Answer

A) there is only a true current through the xy plane 
B) there is only a displacement current through the xy plane 
C) there are both true and displacement currents through the xy plane 
D) there is neither a true nor a displacement current through the xy plane 
E) none of the above are true 
A) there is only a true current through the xy plane 
B) there is only a displacement current through the xy plane 
C) there are both true and displacement currents through the xy plane 
D) there is neither a true nor a displacement current through the xy plane 
E) none of the above are true

Question 14

Two of Maxwell's equations contain an integral over a closed surface.For them the infinitesimal vector area is always:

Accepted Answer

A) tangent to the surface 
B) perpendicular to the surface and pointing outward 
C) perpendicular to the surface and pointing inward 
D) tangent to a field line 
E) perpendicular to a field line 
A) tangent to the surface 
B) perpendicular to the surface and pointing outward 
C) perpendicular to the surface and pointing inward 
D) tangent to a field line 
E) perpendicular to a field line

Question 15

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 16

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 17

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right.Suppose the area is the surface of a piece of paper at which you are looking and is chosen to point toward you.Then, the path integral is:

Accepted Answer

A) clockwise around the circumference of the paper 
B) counterclockwise around the circumference of the paper 
C) from left to right 
D) from right to left 
E) from top to bottom 
A) clockwise around the circumference of the paper 
B) counterclockwise around the circumference of the paper 
C) from left to right 
D) from right to left 
E) from top to bottom

Question 18

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 direction of the induced magnetic field is:

Accepted Answer

A) toward you 
B) away from you 
C) clockwise 
D) counterclockwise 
E) to your right 
A) toward you 
B) away from you 
C) clockwise 
D) counterclockwise 
E) to your right

Question 19

A 0.70-m radius cylindrical region contains a uniform electric field that is parallel to the axis and is increasing at the rate 5.0 *1012 V/m.s.The magnetic field at a point 0.25 m from the axis has a magnitude of:

Accepted Answer

A) 0 T 
B) 7.0 * 10-6 T 
C) 2.8 * 10-5 T 
D) 5.4 * 10-5 T 
E) 7.0 * 10-5 T 
A) 0 T 
B) 7.0 * 10-6 T 
C) 2.8 * 10-5 T 
D) 5.4 * 10-5 T 
E) 7.0 * 10-5 T

Question 20

An electric field exists in the cylindrical region shown and is parallel to the cylinder axis.The magnitude of the field might vary with time according to any of the four graphs shown.Rank the four variations according to the magnitudes of the magnetic field induced at the edge of the region, least to greatest.

Accepted Answer

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

Exam 32: Maxwells Equations; Magnetism of Matter

A small bar magnet is suspended horizontally by a string.When placed in a uniform horizontal magnetic field, it will:

A sinusoidal emf is connected to a parallel plate capacitor.The magnetic field between the plates is:

Which of the following statements is correct?

The intrinsic magnetic dipole moments of protons and neutrons are much less than that of an electron because:

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?

One of the Maxwell equations begins with ....The o symbol in the integral sign means:

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

A magnetic field exists between the plates of a capacitor:

An unmagnetized steel bar is placed inside a solenoid.As the current in the solenoid is slowly increased from zero to some large value, the magnetization of the bar:

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right.For them:

A magnetic field is applied to a paramagnetic substance.In the interior the magnetic field produced by the magnetic dipoles of the substance is:

An electron is on the z axis moving toward the xy plane but it has not reached that plane yet.At that instant:

Two of Maxwell's equations contain an integral over a closed surface.For them the infinitesimal vector area is always:

The magnetic dipole moment of an atomic electron is typically:

Magnetization is:

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right.Suppose the area is the surface of a piece of paper at which you are looking and is chosen to point toward you.Then, the path integral is:

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 direction of the induced magnetic field is:

A 0.70-m radius cylindrical region contains a uniform electric field that is parallel to the axis and is increasing at the rate 5.0 *1012 V/m.s.The magnetic field at a point 0.25 m from the axis has a magnitude of:

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One of the Maxwell equations begins with ....The ^o symbol in the integral sign means:

A 0.70-m radius cylindrical region contains a uniform electric field that is parallel to the axis and is increasing at the rate 5.0 *10¹² V/m.s.The magnetic field at a point 0.25 m from the axis has a magnitude of: