Question 1

The spin magnetic dipole moment of an electron:

Accepted Answer

A) is in the same direction as the spin angular momentum 
B) is zero 
C) has a magnitude that depends on the orbital angular momentum 
D) has a magnitude that depends on the applied magnetic field 
E) none of the above

Question 2

The magnetic properties of materials stem chiefly from:

Accepted Answer

A) particles with north poles 
B) particles with south poles 
C) motions of protons within nuclei 
D) proton spin angular momentum 
E) electron magnetic dipole moments

Question 3

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 4

A magnetic field is applied to a diamagnetic 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

Question 5

Paramagnetism 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 exchange force between electrons 
D) the force exerted by electron dipole moments on each other 
E) the torque exerted by electron dipole moments on each other

Question 6

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 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

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 9

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 10

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 11

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

Question 12

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

Question 13

The diagram shows two small diamagnetic 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 14

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

Question 15

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 1.2 m from the axis has a magnitude of:

Accepted Answer

A) 0 T 
B) 7.0 *10-6 T 
C) 1.1 * 10-5 T 
D) 2.3 *10-5 T 
E) 2.8 * 10-5 T

Question 16

A positively charged ion, due to a cosmic ray, is headed through Earth's atmosphere toward the center of Earth.Due to Earth's magnetic field, the ion will be deflected:

Accepted Answer

A) south 
B) north 
C) west 
D) east 
E) not at all since it is a charge and not a pole

Question 17

A paramagnetic substance is placed in a weak magnetic field and its absolute temperature T is increased.As a result, its magnetization:

Accepted Answer

A) increases in proportion to T 
B) increases in proportion to T2 
C) remains the same 
D) decreases in proportion to 1/T 
E) decreases in proportion to 1/T2

Question 18

A circular parallel-plate capacitor whose plates have a radius of 25 cm is being charged with a current of 1.3 A.What is the magnetic field 11 cm from the center of the plates?

Accepted Answer

A) 4.6 x 10-7 T 
B) 1.0 x 10-6 T 
C) 2.4 x 10-6 T 
D) 3.1 x 10-6 T 
E) 6.2 x 10-6 T

Question 19

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 20

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

Exam 32: Maxwells Equations; Magnetism of Matter