Deck 24: Magnetism

Question 1

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.

Answer 1

exactly 100 N.

Question 2

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.

Answer 2

Choices A and B are both correct.

Question 3

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.

Answer 3

north or south pole - no difference really.

Question 4

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

Question 5

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.

Question 6

Like kinds of magnetic poles repel while unlike kinds of magnetic poles

A)attract.
B)repel also.
C)may attract or repel.

Question 7

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.

Question 8

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.

Question 9

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

Question 10

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

Question 11

Magnetic domains normally occur in

A)iron.
B)copper.
C)silver.
D)all of these
E)none of these

Question 12

Which pole of a compass needle points to a south pole of a magnet?

A)north pole
B)south pole
C)both of these

Question 13

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.

Question 14

Magnetic compasses apparently were first used by

A)Columbus.
B)Greeks.
C)Australian aborigines.
D)Vikings.
E)pigeons,then Chinese.

Question 15

The intensity of cosmic rays bombarding the Earth's surface is largest at the

A)poles.
B)mid-latitudes.
C)equator.

Question 16

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

Question 17

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

Question 18

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.

Question 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.

Question 20

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

Question 21

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.

Question 22

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

Question 23

Outside a magnet,magnetic field lines are conventionally drawn from

A)north to south.
B)south to north.
C)either way

Question 24

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

Question 25

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