Chapter 24 Magnetism
24.1 Questions About Magnetism
1) The source of all magnetism is
A) tiny pieces of iron.
B) tiny domains of aligned atoms.
C) ferromagnetic materials.
D) moving electric charge.
E) none of these
2) Magnetic compasses apparently were first used by
A) Columbus.
B) Greeks.
C) Australian aborigines.
D) Vikings.
E) pigeons, then Chinese.
3) Moving electric charges will interact with
A) an electric field or a magnetic field.
B) only a magnetic field.
C) only an electric field.
D) none of these
4) If a steady magnetic field exerts a force on a moving charge, that force is directed
A) opposite the motion.
B) in the direction of the motion.
C) at right angles to the direction of the motion.
5) If a steady magnetic field exerts a force on a moving charge, that force is directed
A) in the direction of the field.
B) opposite the direction of the field.
C) at right angles to the direction of the field.
6) An iron rod becomes magnetic when
A) positive ions accumulate at one end and negative ions at the other end.
B) its atoms are aligned having plus charges on one side and negative charges on the other.
C) the net spins of its electrons are in the same direction.
D) its electrons stop moving and point in the same direction.
E) none of these
7) Like kinds of magnetic poles repel while unlike kinds of magnetic poles
A) attract.
B) repel also.
C) may attract or repel.
8) Several paper clips dangle from the north pole of a magnet. The induced pole in the bottom of
the lowermost paper clip is a
A) north pole.
B) south pole.
C) north or south pole – no difference really.
9) An iron nail is more strongly attracted to the
A) north pole of a magnet.
B) south pole of a magnet.
C) north or south pole – no difference really.
10) The field surrounding every moving electron is
A) always magnetic but never electric.
B) always electric but never magnetic.
C) sometimes magnetic and sometimes electric.
D) always both electric and magnetic.
E) none of the above
11) Magnetism is due to the motion of electrons as they
A) move around the nucleus.
B) spin on their axes.
C) Choices A and B are both correct.
D) None of the above choices are correct.
12) Magnetic domains normally occur in
A) iron.
B) copper.
C) silver.
D) all of these
E) none of these
13) Magnetic field lines about a current-carrying wire
A) extend radially from the wire.
B) circle the wire in closed loops.
C) Choices A and B are both correct.
D) None of the above choices are correct.
14) The force on an electron moving in a magnetic field will be the largest when its direction is
A) the same as the magnetic field direction.
B) exactly opposite to the magnetic field direction.
C) perpendicular to the magnetic field direction.
D) at an angle other than 90 degrees to the magnetic field direction.
E) none of these
15) The intensity of cosmic rays bombarding the Earth's surface is largest at the
A) poles.
B) mid-latitudes.
C) equator.
16) Which pole of a compass needle points to a south pole of a magnet?
A) north pole
B) south pole
C) both of these
17) Pigeons navigate primarily by
A) a good memory.
B) a keen sense of smell.
C) magnetic sensors in their heads.
D) ultra-high-pitched sounds.
E) none of these
18) Magnet A has twice the magnetic field strength of Magnet B and at a certain distance pulls
on magnet B with a force of 100 N. The amount of force that magnet A exerts on magnet B is
A) at or about 50 N.
B) exactly 100 N.
C) More information is needed.
19) Compared to the huge force that attracts an iron tack to a strong magnet, the force that the
tack exerts on the magnet is
A) relatively small.
B) equally huge.
C) More information is needed.
20) An electron is shot through a spot somewhere between the ends of a horseshoe magnet. The
electron
A) is unaffected by the field.
B) is attracted to one of the poles, and repelled by the other.
C) is repelled by both poles, and therefore is turned back.
D) speed is increased.
E) direction is changed.
21) If a compass is moved from the northern hemisphere to the southern hemisphere, its
magnetic needle will change direction
A) by 180 degrees.
B) depending on where the measurement is taken.
C) by 90 degrees.
D) hardly at all.
E) none of these
22) Outside a magnet, magnetic field lines are conventionally drawn from
A) north to south.
B) south to north.
C) either way
23) Which force field can increase a moving electron's speed?
A) only an electric field
B) only a magnetic field
C) either an electric or magnetic field
D) none of these
24) Which force field can accelerate an electron, but never change its speed?
A) electric field
B) magnetic field
C) both of these
D) none of these
25) Superconducting electromagnets
A) exist now.
B) may be possible in the near future.
C) may be possible in the distant future.
D) are science fiction.