Question 1

Displacement current exists in the region between the plates of a parallel plate capacitor if:

Accepted Answer

A)  the capacitor leaks charge across the plates 
B)  the capacitor is being discharged 
C)  the capacitor is fully charged 
D)  the capacitor is fully discharged 
E)  none of the above are true

Question 2

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

Question 3

The molecular theory of magnetism can explain each of the following EXCEPT:

Accepted Answer

A)  a N pole attracts a S pole 
B)  stroking an iron bar with a magnet will magnetize the bar 
C)  when a bar magnet is broken in two, each piece is a bar magnet 
D)  heating tends to destroy magnetization 
E)  hammering tends to destroy magnetization

Question 4

Which of the following statements is correct?

Accepted Answer

A)  The declination of the Earth's magnetic field is the angle between a horizontal plane and the direction of the field. 
B)  The declination of the Earth's magnetic field is the angle between a vertical plane and the direction of the field. 
C)  The inclination of the Earth's magnetic field is the angle between a horizontal plane and the direction of the field. 
D)  The inclination of the Earth's magnetic field is the angle between the horizontal component of the field direction and the direction to geographic north. 
E)  Inclination and declination mean the same thing.

Question 5

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

Question 6

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

Question 7

The polarity of an unmarked magnet can be determined using:

Accepted Answer

A)  a charged glass rod 
B)  a compass 
C)  an electroscope 
D)  another unmarked magnet 
E)  iron filings

Question 8

A current of 1 A is used to charge a parallel plate capacitor with square plates. If the area of each plate is 0.6 m2 the displacement current through a 0.3 m2 area wholly between the capacitor plates and parallel to them is:

Accepted Answer

A)  2 A 
B)  1 A 
C)  0.7 A 
D)  0.5 A 
E)  0.25 A

Question 9

What are the possible allowed values of the orbital magnetic quantum number mℓ of the electron?

Accepted Answer

A)  0 only 
B)  0, ±1 only 
C)  any half-odd integer 
D)  0, ±1, ±2, …, up to the maximum value for that orbit 
E)  It depends on the external magnetic field.

Question 10

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

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

Question 12

According to Gauss' law for magnetism, magnetic field lines:

Accepted Answer

A)  form closed loops 
B)  start at south poles and end at north poles 
C)  start at north poles and end at south poles 
D)  start at both north and south poles and end at infinity 
E)  do not exist

Question 13

If an electron has zero orbital angular momentum, the magnitude of its magnetic dipole moment equals:

Accepted Answer

A)  zero 
B)  half the Bohr magneton 
C)  a Bohr magneton 
D)  twice a Bohr magneton 
E)  none of these

Question 14

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

Accepted Answer

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

Question 15

The magnetic field lines due to an ordinary bar magnet:

Accepted Answer

A)  form closed curves 
B)  cross one another near the poles 
C)  are more numerous near the N pole than near the S pole 
D)  leave the S pole, loop around the outside of the magnet, and enter the N pole 
E)  none of the above

Question 16

Magnetic dipole X is fixed. Dipole Y is placed in the position indicated and is free to move. The first thing dipole Y will do is:

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 move toward or away from X

Question 17

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

Question 18

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

Question 19

Lenz' law can explain:

Accepted Answer

A)  paramagnetism only 
B)  diamagnetism only 
C)  ferromagnetism only 
D)  only two of the three types of magnetism 
E)  all three of the types of magnetism

Question 20

Maxwell's equations, along with an appropriate symmetry argument, can be used to calculate:

Accepted Answer

A)  the electric force on a given charge 
B)  the magnetic force on a given moving charge 
C)  the flux of a given electric field 
D)  the flux of a given magnetic field 
E)  none of these

Exam 32: Maxwells Equations; Magnetism of Matter